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1970 Opel Gt - Purchased July 1972 - Chartreuse - restored - 3000 miles as of 02-16, 2021 -
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Discussion Starter · #1 ·
I have been reading up on head lights and how they are routed through relays and how there seems to be a number of variations, on wiring, variations either made by the the PO, a mechanic trying to make it work, or made by the manufacturer depending on the year of the GT. I have spent three four hour afternoons lying on my back looking up at this fuse box, testing connections - trying to figure it out, and would appreciate some help if this sounds like something you have been through. So these are the facts:
  • Head lights are too dim on the low setting - I would guess around 50 % too dim
  • I replaced headlight wiring harness was with a new wiring harness in 2000 - not a 70 model as it had a few more wires than the one I was replacing - the car has been in a garage and has only been driven 2700 mile since that time although I believe the dim head lights go way back, I think back 39 years or so - when I replaced the head light wiring harness I assumed it would be cured
  • I have cleaned the 4 main contacts on the fuse box so they now register the same as a direct read from the battery/ starter solenoid so plenty of power to that point 12.3
  • There is an anomaly in the relay wiring - Looking at the instruction for relay testing - D which is on the 7 prong relay is suppose to be "white/yellow striped wire # 87 this wire splits which carry 7-prong relay output power to 5 prong relay inputs labeled E " - My GT has no wire attached to that prong that connection is plugged into the fuse box, laying on your back looking up, closest to front of car second from the left/ passenger side front - don't think this is part of the issue but not sure - this prong with wire attached and lights on reads 4.15 volts on the multi-meter - to my knowledge the car came like this and again I don't think that is part of the issue
  • All of the other prongs read around 9.5 on both relays, while the battery and the 4 main fusebox connections were at 12.3 - keep in mind that I have been doing a lot of testing over the past three days do that is why the battery is low, as it is new - that is the ones that are supposed to have power
  • The gauge lights work only on the speedometer and the tach - the amp meter idiot lights come on when car is turned on but not the gauge lights on the three small gauges
  • High beam low beam switch is working, blinkers, everything else - the passenger blinker indicator does double blink but still works fine
  • So just a thought, with the lights on the 9.5 on the relays would that just be a function of the power drain from 12.3 to 9.5 or should it read 12.3 as well. Do I need to retest this with the car running however in the past lights were also dim with the car running
  • I guess one possibility is the relay needs to be replaced but it does past the test - seems odd that the voltage is lower on all of the relay contacts except the one that is around 4.15
Thanks for your comments, Carl
 

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Carl, I am in the same boat with the gauges. They worked 10 days ago, now none of them work. I will figure it out. I take that back, the speedometer still works.

Sometimes the headlights need to be upgraded. they just get worn out and need to be replaced. I have used LED lights for all the lights on my GT. My lights wer not as bad as yours, but they were losing brightness little by little.

Bob
 

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Well, dim headlights was always the traditional way I discovered that my battery wasn't charging due to bad alternator.....or weak battery, but you're not running the engine. As a general rule, you should be reading full battery voltage wherever you check the Head/Park light voltage, except the instrument panel dimmer switch output, which of course will vary.

So, step one is: Do you have full voltage at the wires plugged into your headlights? If you have full voltage at the headlights but they are still dim, then the headlights are the problem. Another way is to run jumper wires directly from the battery to the device, in this case: The headlight bulbs. 12 volts should make both the hi and lo beam circuits in the bulbs light up equally

At my Post Office job, we were taught a basic testing principal on day one: Go to the end of the circuit and test for power, if it's not there(or in your case not enough power), then go half way back in the circuit and test again, keeping dividing and conquering until you find the power loss. Power in our PO machines would sometimes go through 30 daisy chained switches, circuit boards, etc., so cutting the problem in half saves you from randomly testing 30 switches and jumping all over the place without a plan. After I was taught that principal I actually used it to fix a problem on my Opel just days after being taught it......and it was a lighting system problem.

In general, on our cars the problem is almost always at the colored connectors at the fuse box or with the grounding of the various devices. You can have full voltage going to a device, but the ground is poor. Grounding is such a problem in our cars that when I built my GTX car with a new aftermarket fuse box I ran ground return wires back from every single light and device back to a single grounding point in that area. I have 3 of those points: One in the engine compartment on one of the big bolts on the brake booster support bar, one behind the dash, and one behind the seats under the luggage shelf. Nice stainless steel bolts on bare metal at each location. You must of course then also make sure that your negative of the battery has good ground to the body and engine, I use a stainless bolt screwed in at the normal engine/battery grounding point on the passenger side frame rail next to the engine.

Give that stuff a whirl and check your colored fuse box connectors(jiggle the ones that have lighting power while you are testing to see if it makes the power reading on your voltmeter fluctuate.
 

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This will be an interesting read/ Diagnosis. I'm glad you brought this up Carl. When I bought my gt (73) Among all the things that didn't work including every aspect of the head lights not locking open or closed very hard to turn and just not working at all. My son and I pulled the buckets and all the parts that were attached. We found the bucket actuators rusted up and extremely dirty, the locks stuck all the micro relays shot and bypassed and the wiring from the light bulbs to the fire wall a disaster and all most nothing more than a rats nest of frayed wires. Once we corrected all there was from the fire wall to the lights we were shocked that the main relays in the fuse panel still worked. we can roll the lights to the locked position and reverse with two fingers. However low beam is as you say so dull yellow/orange when we drove at night we had to run on high beams to see anything. We just assumed that this is what it is and would replace the light bulbs later and see if it helps.
What I do find interesting is not only the extreme difference in the brightness from low to high but the clarity of the light as well. I'll keep tuned in to see what the outcome becomes. We weren't in any hurry to pursue the fix simply cause we/I don't drive it at night anyway But if I do or have to it would be nice to see where I'm going and not have oncoming traffic flashing me cause I'm running on high beams to see
 

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Discussion Starter · #6 ·
12,3 V is low, a healthy battey should have around 12,7 V. Charge it before it gets damaged.
  • Thanks Commodaren, We can rule out the battery as mine is brand new as is the alternator - with all the testing the battery had run down a little over the past three days as I am not running the engine in the garage, not yet anyway!! I will put a charge on it right now.
 

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Discussion Starter · #7 ·
Carl, I am in the same boat with the gauges. They worked 10 days ago, now none of them work. I will figure it out. I take that back, the speedometer still works.

Sometimes the headlights need to be upgraded. they just get worn out and need to be replaced. I have used LED lights for all the lights on my GT. My lights were not as bad as yours, but they were losing brightness little by little.

Bob
Thanks Bob, My head lights are new, that is the old fashion three prong bulbs from the old days. Regarding the gauge lights funny that two out of 5 are working for me. I have a feeling that is going to be something came loose last time I took out the instrument panel will let you know if I figure it out. While I was spending all that time staring at my fuse box I did finally get around to fixing one thing that I have a feeling a lot of people have an issue with. The steering column wiring plugs into the fuse box. With the plugs removed I was able to use needle nose pliers to pull the inter housing, that the plugs fit into out to where they belonged - then cut a couple slivers, litttle under a 1/4 inch of wood off the width of a paint stir stick, which was the perfect length, and JB welded the seams using the wood to add strength. Worked like a charm and I don't know why I did not do this years ago. Any the plugs now go in all the way and will actually stay plugged in. Pretty sure this is what brought back my high beam switch.
 

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A common wet type battery should never be drained to less than 50% of its capacity to avoid sulfation of its lead plates. The result will be a lower capacity for every discharge over 50%. And a battery should also always be stored fully charged between usages. I have an 80Ah gel battery for my electric 55lb Minn Kota fishing motor that is still going strong after 9 years of use, but I have never discharged it over 50% and always charged it full immediately after coming home from fishing .
 

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Providing battery voltage is correct. 99% of the time dim lights, signal crossing, gauges moving when they shouldn't, etc. can be traced to poor grounding. Electricity will search for a path to ground and without a proper one, it will take any available route it can find to get there, usually affecting something else along the way. Opel's in particular have exceptionally poor grounding, a fact that only gets worse with age. Fortunately testing for a possible grounding problem is one of the easiest things to do. Clip a long wire to your negative battery post and touch the other end to the ground terminal of the headlight, gauge or whatever you are having a problem with. If it's a grounding issue your problem will disappear. Obviously it should go without saying, be sure you know EXACTLY which terminal is the ground point.
 

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  • There is an anomaly in the relay wiring - Looking at the instruction for relay testing - D which is on the 7 prong relay is suppose to be "white/yellow striped wire # 87 this wire splits which carry 7-prong relay output power to 5 prong relay inputs labeled E " - My GT has no wire attached to that prong that connection is plugged into the fuse box, laying on your back looking up, closest to front of car second from the left/ passenger side front - don't think this is part of the issue but not sure - this prong with wire attached and lights on reads 4.15 volts on the multi-meter - to my knowledge the car came like this and again I don't think that is part of the issue
I am not sure what diagram you have, but I'm trying to interpret the above based on reading the FSM schematic.

That Wht/Yel wire between relays sounds like the heavy 12 ga wire that should feed the power from the 7 prong headlamp relay into the 5 prong headlamp dimmer relay. That 5 prong dimmer relay sends the 12v headlamp power to either the high or low beam filaments in the bulb. It sounds like someone moved that power feed to one of the 3 other outputs of the 7 prong headlamp relay, which are on the 3 positions on the fuse block that feed to the license plate lamps, tail and parking lamps, etc. Why this was moved, IDK, but it is possible that the main headlamp contacts got burned out in the 7 prong relay, and someone moved it to one of that relay's other contact outputs.

If it is really reading 4.1v on the prong feeding power into the 5 prong dimmer relay,, then that is a big problem; that voltage into the 5 prong relay should be only a few tenths of a volt lower than the battery voltage at worst.

Do as Gordo sez, and with the low beams on, measure the voltage at the4 headlamp itself on the low beam side. If it 4.1v, then your problem is in that wire feeding power into the 5 prong relay. Check the voltage where that Wht/Yel power feed wire connects into the fuse box. It that is also at 4.1v, then the problem is in the wiring between the fuse block point and the 7 prong relay...OR, that other contact in the 7 prong relay feeding that point on the fuseblock is just not designed to handle the headlamp current, or is also burned.

If the above guesses are right, then you are probably looking at a new headlamp relay. The fact that you have 9.5v out of the other 7 prong headlamp relay contacts going to the fuse block sez that something is very probably burned up in the headlamp relay. Then you can properly connect the power feed into the 5 prong dimmer relay to the main power output of the 7 prong relay... as it should be.

As a test of the 5 prong dimmer relay, you can disconnect that Wht/Yel power feed wire going to the 5 prong relay and temorarily jumper battery power directly into that wire; the headlamps then should be fully bright if there are not other wiring problems between that dimmer relay and the headlamps, and that relay's contacts are not also burned on either high or low beams contacts.

Hope that helps!
 

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First of all, it is imperative that the battery be fully charged. If it is not fully charged, strange and unexplainable things will happen. I can give examples.

You do not say but the suggestion is there that the high-beam function works satisfactorily -- the lamps are bright. This being the case, then you can eliminate "bad ground" as your problem. Each sealed beam is grounded individually (the right-side beam is co-grounded with the right-side indicator lamp switch). Otherwise, the two other grounds are at the high-beam switch on the steering column, which obviously works; and the #85 terminal on the headlamp relay.

With the high beams working, it would appear that the issue lies with the dimmer relay. The #12 Yellow wire connected to the #56B terminal is your low beam. Connect a known hot wire to this connection and see if the illumination improves. If it does, then either the connection at the dimmer relay is poor or the relay itself is gone. Otherwise, check the connections at the sealed beams. A defective headlamp relay or bad connections at any of the terminals would have an adverse effect on both high and low beam functions.
 

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Manta raises a good point that I failed to address because of a bad assumption on my part, that the relays are all connected properly. However, the fact that the high beams do work would suggest that the connections are correct. But the current path of the circuit is as follows:

The 12-g Black wire from the hot side of the fuse block powers the headlamp relay microswitch behind the left-side headlamp unit. When the buckets open, this switch closes and connects a 12-g Yellow-Black wire

The Yellow-Black wire runs to post #85 on the headlamp relay, connecting internally an electromagnet that closes a switch connecting the 30/51 post with the #87 post. The 30/51 post receives current from a 12-G red wire from the hot side of the fuse block.

The #87 post has four connections. Three of them power the instrument panel lamps and the side marker/parking/tail lamps. Ignore them for the moment and concentrate on the fourth connection, the double-connected 12-g White-Yellow wire. One of these wires runs to the right-side headlamp indicator switch. Ignore it for the moment. The other White-Yellow connects to the #56 terminal of the Dimmer Relay.

Coming off the Dimmer Relay you have the 20-g Green wire connected to the "S" terminal, running to the dimmer switch. This apparently works as intended.

The Dimmer Relay is wired internally so that the dimmer switch grounds the 20-g Green wire, activating an electromagnetic switch that connects power from the #56 terminal to the #56A terminal

The #56A Post of the Dimmer Relay is the High-Beam function, with two 12-g White wires, one running to the high beam terminal of the sealed beams and the other to the high-beam indicator lamp on the instrument panel.

The #56B Post on the Dimmer Relay is the Low-Beam function with a 12-g Yellow wire to the low beam terminal of the sealed beams.

The headlamp open/closed indicator switches will not affect operation of the headlamps.
 

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Discussion Starter · #13 ·
Well, dim headlights was always the traditional way I discovered that my battery wasn't charging due to bad alternator.....or weak battery, but you're not running the engine. As a general rule, you should be reading full battery voltage wherever you check the Head/Park light voltage, except the instrument panel dimmer switch output, which of course will vary.

So, step one is: Do you have full voltage at the wires plugged into your headlights? If you have full voltage at the headlights but they are still dim, then the headlights are the problem. Another way is to run jumper wires directly from the battery to the device, in this case: The headlight bulbs. 12 volts should make both the hi and lo beam circuits in the bulbs light up equally

At my Post Office job, we were taught a basic testing principal on day one: Go to the end of the circuit and test for power, if it's not there(or in your case not enough power), then go half way back in the circuit and test again, keeping dividing and conquering until you find the power loss. Power in our PO machines would sometimes go through 30 daisy chained switches, circuit boards, etc., so cutting the problem in half saves you from randomly testing 30 switches and jumping all over the place without a plan. After I was taught that principal I actually used it to fix a problem on my Opel just days after being taught it......and it was a lighting system problem.

In general, on our cars the problem is almost always at the colored connectors at the fuse box or with the grounding of the various devices. You can have full voltage going to a device, but the ground is poor. Grounding is such a problem in our cars that when I built my GTX car with a new aftermarket fuse box I ran ground return wires back from every single light and device back to a single grounding point in that area. I have 3 of those points: One in the engine compartment on one of the big bolts on the brake booster support bar, one behind the dash, and one behind the seats under the luggage shelf. Nice stainless steel bolts on bare metal at each location. You must of course then also make sure that your negative of the battery has good ground to the body and engine, I use a stainless bolt screwed in at the normal engine/battery grounding point on the passenger side frame rail next to the engine.

Give that stuff a whirl and check your colored fuse box connectors(jiggle the ones that have lighting power while you are testing to see if it makes the power reading on your voltmeter fluctuate.
Thanks Gordon,

I spent another 4 hours reading, testing, experimenting - felt like science class all over again. Thanks for all of the information! Checked your recommendations:
  • I recently removed my engine to chassis strap and cleaned it really well and both connections - also checked the head light grounds near the master cylinder - all good
  • My ground to the battery is also stainless - my power reads the same at the battery, starter solenoid and the 4 main terminals in the fuse box - this morning 12.7
  • I checked the low and high beams using a negative ground from the battery which made no difference
  • Something that was surprising, while attaching an extra bulb that I have directly to the battery both + and - The brightness was pretty close to the bulbs installed in the car. That was straight 12 volt - voltage could have dropped a little from the testing but still I was expecting a big difference at least on the low beam setting
  • Speaking of science class, while I had the hats off the head lights checking the voltage I happened to touch that ground wire from the negative battery terminal to the white wire and I was expecting sparks to fly, like when I touch the yellow wire by mistake but guess what - the lights got a lot brighter and the voltage meter read .37 and no sparks - I don't know much about electricity but what am I missing here. Again I touch that extra negative ground to the white wire and the lights got brighter?
  • I then discovered that I had in fact attached the wrong wires to the wrong prongs so now they are correct with yellow to the left brown in the middle and white on the right - good news is that the voltage went from a little over 4 to 5.6 for the low beam and is now over 10 volts for the high beams. Making progress...
 

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Discussion Starter · #14 ·
I am not sure what diagram you have, but I'm trying to interpret the above based on reading the FSM schematic.

That Wht/Yel wire between relays sounds like the heavy 12 ga wire that should feed the power from the 7 prong headlamp relay into the 5 prong headlamp dimmer relay. That 5 prong dimmer relay sends the 12v headlamp power to either the high or low beam filaments in the bulb. It sounds like someone moved that power feed to one of the 3 other outputs of the 7 prong headlamp relay, which are on the 3 positions on the fuse block that feed to the license plate lamps, tail and parking lamps, etc. Why this was moved, IDK, but it is possible that the main headlamp contacts got burned out in the 7 prong relay, and someone moved it to one of that relay's other contact outputs.

If it is really reading 4.1v on the prong feeding power into the 5 prong dimmer relay,, then that is a big problem; that voltage into the 5 prong relay should be only a few tenths of a volt lower than the battery voltage at worst.

Do as Gordo sez, and with the low beams on, measure the voltage at the4 headlamp itself on the low beam side. If it 4.1v, then your problem is in that wire feeding power into the 5 prong relay. Check the voltage where that Wht/Yel power feed wire connects into the fuse box. It that is also at 4.1v, then the problem is in the wiring between the fuse block point and the 7 prong relay...OR, that other contact in the 7 prong relay feeding that point on the fuseblock is just not designed to handle the headlamp current, or is also burned.

If the above guesses are right, then you are probably looking at a new headlamp relay. The fact that you have 9.5v out of the other 7 prong headlamp relay contacts going to the fuse block sez that something is very probably burned up in the headlamp relay. Then you can properly connect the power feed into the 5 prong dimmer relay to the main power output of the 7 prong relay... as it should be.

As a test of the 5 prong dimmer relay, you can disconnect that Wht/Yel power feed wire going to the 5 prong relay and temorarily jumper battery power directly into that wire; the headlamps then should be fully bright if there are not other wiring problems between that dimmer relay and the headlamps, and that relay's contacts are not also burned on either high or low beams contacts. I think the reason it was moved is because that vacant prong D is only carring around .16 voltage.

Hope that helps!
Thanks Bob,
  • Regarding your first paragraph - I think you are right as the prong on the end of the row of 4 is empty, however the instructions from OGTS call out that wire D from DIJK to be for White yellow striped wire (87) - this wire splits into two wires which carry 7 prong relay output power to 5 prong relay inputs labeled E. And by the way those two prongs are reading over 10 volts. That vacant prong is in fact carrying around .16 volts???
  • I did the test you mentioned adding 12 volts to the the white yellow power feed wire-which is currently at 5.65 volts and non difference to the low beam brightness - so I guess this is telling me about a new relay being in my future
 

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1. That Wht/Yel wire between relays sounds like the heavy 12 ga wire that should feed the power from the 7 prong headlamp relay into the 5 prong headlamp dimmer relay. That 5 prong dimmer relay sends the 12v headlamp power to either the high or low beam filaments in the bulb. It sounds like someone moved that power feed to one of the 3 other outputs of the 7 prong headlamp relay, which are on the 3 positions on the fuse block that feed to the license plate lamps, tail and parking lamps, etc. Why this was moved, IDK, but it is possible that the main headlamp contacts got burned out in the 7 prong relay, and someone moved it to one of that relay's other contact outputs.

2. If it is really reading 4.1v on the prong feeding power into the 5 prong dimmer relay,, then that is a big problem; that voltage into the 5 prong relay should be only a few tenths of a volt lower than the battery voltage at worst.

3. As a test of the 5 prong dimmer relay, you can disconnect that Wht/Yel power feed wire going to the 5 prong relay and temorarily jumper battery power directly into that wire; the headlamps then should be fully bright if there are not other wiring problems between that dimmer relay and the headlamps, and that relay's contacts are not also burned on either high or low beams contacts.
#1 is not exactly correct. There is no "correct" ordering of the four wires, as all four of the contacts connect internally at the #87 terminal of the Headlamp Relay. It is possible that the internal switch is corroded to the extent that it will not transfer the voltage from #30/51, but in that case you would expect to see poor performance of all other lamps -- dash, side marker and tail lamps. That being the case, a new headlamp relay would be in order. If everything else works, it is possible that the one connection terminal for the White-Yellow wire is corroded or simply loose.

#2 is a correct statement. Again, look for a loose or corroded connection. Also, test the voltage output at all four #87 terminals of the Headlamp Relay. They should be the same. If they are all low, you have a bad Headlamp Relay.

#3 is correct. If you have full voltage going into the Dimmer Relay at Terminal #56, then you should have the same voltage coming out at #56B. Note that there is supposed to be a 12-g White-Yellow wire connecting the #56 terminal to the "S" terminal in the Dimmer Relay
 

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Discussion Starter · #16 ·
Manta raises a good point that I failed to address because of a bad assumption on my part, that the relays are all connected properly. However, the fact that the high beams do work would suggest that the connections are correct. But the current path of the circuit is as follows:

The 12-g Black wire from the hot side of the fuse block powers the headlamp relay microswitch behind the left-side headlamp unit. When the buckets open, this switch closes and connects a 12-g Yellow-Black wire

The Yellow-Black wire runs to post #85 on the headlamp relay, connecting internally an electromagnet that closes a switch connecting the 30/51 post with the #87 post. The 30/51 post receives current from a 12-G red wire from the hot side of the fuse block.

The #87 post has four connections. Three of them power the instrument panel lamps and the side marker/parking/tail lamps. Ignore them for the moment and concentrate on the fourth connection, the double-connected 12-g White-Yellow wire. One of these wires runs to the right-side headlamp indicator switch. Ignore it for the moment. The other White-Yellow connects to the #56 terminal of the Dimmer Relay.

Coming off the Dimmer Relay you have the 20-g Green wire connected to the "S" terminal, running to the dimmer switch. This apparently works as intended.

The Dimmer Relay is wired internally so that the dimmer switch grounds the 20-g Green wire, activating an electromagnetic switch that connects power from the #56 terminal to the #56A terminal

The #56A Post of the Dimmer Relay is the High-Beam function, with two 12-g White wires, one running to the high beam terminal of the sealed beams and the other to the high-beam indicator lamp on the instrument panel.

The #56B Post on the Dimmer Relay is the Low-Beam function with a 12-g Yellow wire to the low beam terminal of the sealed beams.

The headlamp open/closed indicator switches will not affect operation of the headlamps.
Thanks Michael,
  • Yes the high beam function works fine - it did not, the switch, last week but my fiddling around with the plugs from the steering column and getting a tighter fit seems to have corrected that problem.
  • 56B terminal has over 11 volts
  • Sealed beams are over 10 to 11 on high beam and 5.6 on low beam at the light bulb
  • The 87 four in line connections has one that is almost dead, maybe .16 volts so that wire is in the fuse box number 3 from the shifter and has a voltage reading of around 10.5 however at the prong connection it is 5.6
I am going to recheck all the numbers tomorrow with a fully charged battery, but based on the comments it appears that a new relay is required, or do I need both. When I added the 12 volts to the connection it still read 5.6.
Anyway I want to thank everyone for your suggestions/recommendations as it all served me well and I have learned a lot. Looks like after a retest tomorrow if nothing changes I will order the relay. I am pretty sure this is an issue that goes back to 1981. Its a long story but I have a specific memory about dim head lights in November of that year when my first daughter way born - like I said earlier I assumed that the new lighting wiring harness would have taken care of it but not so. This will be the first time I have purchase a new car one part at a time. It has no doubt been a challange but a lot of fun along the way. This forum keeps me going. Thanks all. Carl
 

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If you have 11 volts at terminal #56B coming out of the dimmer relay and only 5.6 volts at the sealed beam, then there is a problem with the Yellow wire from Terminal 56B to the sealed beam. Possibly a bad connection or possibly a break. The wiring schematics do not show this wire going through any connectors -- it is a straight run from the relay to the beam. There is a connection up front branching the circuit to both headlamps -- this connection may be bad.
 

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I am thinking that the terminal on the Headlamp Relay where you are measuring 5.6 volts may be terminal #86. This terminal is to be grounded. Internally, terminal #85 and #86 have between them an electromagnet. When the headlamps open ("On"), the micro-switch behind the left bucket mechanism closes as switch that connects power from the 12-g Black wire (from the hot side of the fuse box). to terminal #85 via a 12-g Yellow-Black wire that, because #86 is grounded, activates the electromagnet, causing a voltage drop at #86. You would have less energy too if you were run through a coil of wire.

This gets back to the earlier point that the connections to the various terminals have to be absolutely correct.

Red wire to terminal #30/51
Yellow-Black wire to terminal #85
#86 is grounded (color not indicated on schematics -- could be Brown or the relay could be internally grounded)
White-Yellow to one of the four connectors on Terminal #87

There are three other wires that connect to Terminal #87"
Gray-Green routes to the parking light switch, the instrument panel dimmer switch, and the license plate lamps (#1 fuse)
Gray-Red routes to the turn signal switch, the parking lamp switch and to the right-side side markers and tail lamp (#2 fuse)
Gray-Black routes also routes to the turn signal and parking lamp switches, and to the left-side side markers and tail lamps (fuse #3),
 

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Thanks Michael,
  • Yes the high beam function works fine - it did not, the switch, last week but my fiddling around with the plugs from the steering column and getting a tighter fit seems to have corrected that problem.
  • 56B terminal has over 11 volts
  • Sealed beams are over 10 to 11 on high beam and 5.6 on low beam at the light bulb
  • The 87 four in line connections has one that is almost dead, maybe .16 volts so that wire is in the fuse box number 3 from the shifter and has a voltage reading of around 10.5 however at the prong connection it is 5.6
I am going to recheck all the numbers tomorrow with a fully charged battery, but based on the comments it appears that a new relay is required, or do I need both. When I added the 12 volts to the connection it still read 5.6.
Anyway I want to thank everyone for your suggestions/recommendations as it all served me well and I have learned a lot. Looks like after a retest tomorrow if nothing changes I will order the relay. I am pretty sure this is an issue that goes back to 1981. Its a long story but I have a specific memory about dim head lights in November of that year when my first daughter way born - like I said earlier I assumed that the new lighting wiring harness would have taken care of it but not so. This will be the first time I have purchase a new car one part at a time. It has no doubt been a challange but a lot of fun along the way. This forum keeps me going. Thanks all. Carl
If the diagrams in the FSM are correct, and properly show what is inside the relays then...... One of the 2 dimmer relay outputs, 56A or 56B, should only have voltage on it when the high beams are on. (You seem to indicate that is terminal 56B.) The other output should have voltage on it when either the high or low beams are on; that terminal should go to the low beam filaments. (So that the low beam filaments get fed power in both states per that FSM diagram.) So figure out which terminal is on in both states and that should be the low beam terminal. I think it ought to be the 56A terminal per the diagrams. I am guessing that you will see the 4-5-6 volts there whenever the low beams are active.

Next, disconnect both headlight connectors to remove the load from all contacts inside the dimmer relay, and check voltage at both the 56A and 56B contacts with the low beam active, and then the high beams active. With the low beams active, if the voltage on the low beam terminal is 11-12 volts, then the internal contact for the low beams inside the dimmer relay is burned up, and is dropping the voltage at that terminal to 4-5-6 volts when the low beams filaments are on.

What you say about 1 of the 4 terminals on 87 being dead makes sense; I think there are 4 separate ouput contacts that get connected internally to a common power contact inside the headlamp relay when the headlamp relay is engaged. The headlight current is a lot higher than the other loads (like side marker lamps etc.) and that particular output contact feeding the headlights will always burn out 1st. So I am pretty sure that is why the Wht/Yel power wire going to the dimmer relay got moved from that 4th terminal. That all says that it is time for a new headlamp relay. Or, add a new relay for just the power to that 12 ga Wht/Yel, and activate that new relay from one of the other 3 outputs on the existing headlamp relay.
 
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