Simplified headlight wiring

[thescifiguy]

My previous '70 GT had had the headlights rewired and simplified to come on when the parking light switch was flicked. The flip mechanism microswitches were eliminated, so that with a single flip of the switch all the lights came on....like a normal car. This was particularly nice, especially if your flip mechanisms were worn out and wouldn't reliably lock in place and activate the micros. I liked driving my GT with it's eyes open(headlights up), but with stock wiring, that meant that the lights would be on all the time. Seldom do you need your parking lights on and not your headlights, too.

I'd like to do this modification to my new GT, but I'm told that I can't just wire the headlights to the switch 'cuz it can't handle the power. I guess it might be able to be done using the existing headlight relay or maybe another relay like the ones we add to bypass the ignition switch.

Can an electrical Guru out there suggest the wiring sequence to pull off this sort of modification?

[jerseydave]

I think this has been covered but if I recall I remember a lot of reference to:

Daniel Stern Lighting Consultancy and Supply

[markandson]

Should be very easy to do I don't have a schematic with me but I'm sure someone else will chime in, if not I can help you in a few days.

[First opel 1981]

Originally Posted by thescifiguy My previous '70 GT had had the headlights rewired and simplified to come on when the parking light switch was flicked. The flip mechanism microswitches were eliminated, so that with a single flip of the switch all the lights came on....like a normal car. This was particularly nice, especially if your flip mechanisms were worn out and wouldn't reliably lock in place and activate the micros. I liked driving my GT with it's eyes open(headlights up), but with stock wiring, that meant that the lights would be on all the time. Seldom do you need your parking lights on and not your headlights, too. I'd like to do this modification to my new GT, but I'm told that I can't just wire the headlights to the switch 'cuz it can't handle the power. I guess it might be able to be done using the existing headlight relay or maybe another relay like the ones we add to bypass the ignition switch. Can an electrical Guru out there suggest the wiring sequence to pull off this sort of modification?

A quick look at the wiring diagram suggests the following easy connection change will work (in theory, because I haven't tested it yet)

1) Disconnect the yellow/black wire from the headlight relay and tape off
Wiring1.jpg
2) Connect a jumper from the disconnected lug in step 1 and connect the other end of the jumper to the fuse block position as shown in the attached picture
Wiring2.jpg

That should do it

[markandson]

Find the yellow wire with the black stripe on the headlight relay, pull it off and tape it up, this is the wire that becomes "hot" when the micro-switch is activated by the headlights being open. Find a wire at the fuse box that is Grey with a red stripe, which should be at the second fuse, this is the wire that feeds the front marker lights, run a jumper from this spot over to the terminal on the headlight relay. That should do it, you will now be powering up the headlight relay whenever you turn on the marker lamps.

[First opel 1981]

Originally Posted by markandson Find the yellow wire with the black stripe on the headlight relay, pull it off and tape it up, this is the wire that becomes "hot" when the micro-switch is activated by the headlights being open. Find a wire at the fuse box that is Grey with a red stripe, which should be at the second fuse, this is the wire that feeds the front marker lights, run a jumper from this spot over to the terminal on the headlight relay. That should do it, you will now be powering up the headlight relay whenever you turn on the marker lamps.

That should work too though, in theory, you are now powering the headlight relay through the marker lights circuit.

[markandson]

Originally Posted by First opel 1981 A quick look at the wiring diagram suggests the following easy connection change will work (in theory, because I haven't tested it yet) 1) Disconnect the yellow/black wire from the headlight relay and tape off Attachment 21767 2) Connect a jumper from the disconnected lug in step 1 and connect the other end of the jumper to the fuse block position as shown in the attached picture Attachment 21768 That should do it

I don't think so, I think you are connecting to the wrong side of the fuse block and also to the instrument light circuit which runs through the rheostat which should not see any more load. The second or third fuses and the opposite side of the fuse block have wires that are fuse protected and run the left and right marker lights in the front, I think these are the connection points he should use.

[markandson]

Originally Posted by First opel 1981 That should work too though, in theory, you are now powering the headlight relay through the marker lights circuit.

Yup, that is exactly what I am trying to do.

[First opel 1981]

Originally Posted by markandson I don't think so, I think you are connecting to the wrong side of the fuse block and also to the instrument light circuit which runs through the rheostat which should not see any more load. The second or third fuses and the opposite side of the fuse block have wires that are fuse protected and run the left and right marker lights in the front, I think these are the connection points he should use.

I was referencing the direct point from the running light switch, not the instrument lights.
On the wiring diagram I am looking at (I believe its the MEGA wiring diagram) the running light switch is the point that he should connect to.
Running it through the running lights themselves will work, as I said in my reply to your suggestion. I just thought it would be better to go all the way back to the switch for the power source for the relay.

I might have read the running light switch wrong, and if I did I will concede.

[markandson]

No conceding necessary one way or the other, we are both just trying to help a fellow Opeler.

[wrench459]

why not control the ground (brown) wire off the headlamp relay?
And why not control all the power wires going to the lights?
The headlamp relay is just a big bridge to power up the all the lights.
Can you say more relays? Sounds simple

[First opel 1981]

Originally Posted by wrench459 why not control the ground (brown) wire off the headlamp relay? And why not control all the power wires going to the lights? The headlamp relay is just a big bridge to power up the all the lights. Can you say more relays? Sounds simple

Control the ground wire? Hmmmmm.
Nope, I don't see it.

[markandson]

Originally Posted by First opel 1981 Control the ground wire? Hmmmmm. Nope, I don't see it.

Me either, why mess with the way the system works if all you need to do is supply power to the headlight relay from a different source?

[wrench459]

Originally Posted by markandson Me either, why mess with the way the system works if all you need to do is supply power to the headlight relay from a different source?

Like a PNP switch?
I would just hate to modernize a old car.

[markandson]

Originally Posted by wrench459 Like a PNP switch?

Nope....don't have to P just like a switch switch

[wrench459]

Oh crap I've just got a warm feeling going......

[thescifiguy]

So, are we running the full power for the headlights and markers through the switch or is the main current flowing through the relay and the switch is just enabling the relay? The latter set up being the more desirable option.

By the way, THANKS GUYS for saving me the trouble of working out the circuit myself!

[wrench459]

Originally Posted by thescifiguy So, are we running the full power for the headlights and markers through the switch or is the main current flowing through the relay and the switch is just enabling the relay?

Yep the relay is handling the main current draw of the headlamps.
The switch just controls the field coil of the relay.

[thescifiguy]

Well, guys, I tried the jumper wire from the indicated fuze box location to the yellow/black location on the headlight relay and what I get is a holding circuit that won't turn off.....even with all switches off and the key removed, the headlights won't turn off until you unplug the wire. Put the key in, plug in the jumper wire-----headlights are still off-----advance key to the run position---lights are still off----- flick the parking light switch and all the lights come on. Now you can't turn them off. Flick the switch, remove the key, they're still on. I even tried a different fuze/location on the fuze box and it still happens.

I tried this a buncha weeks ago when you guys gave me the info and the same thing happened. I thought I'd check out the wiring before I got us grasping at straws. I'm pretty sure things are right.

Any ideas?

[rsefczek]

i pulled one of the parking light wires from the fuse box and plugged it into the y/b position on the relay. when you flip the parking switch it now sends a current to the relay to trigger the headlights. no jumpers or wires to cut but you have to have enough slack in the parking light wire to reach the relay.
good luck!

bob

[opelnut10]

Originally Posted by thescifiguy Well, guys, I tried the jumper wire from the indicated fuze box location to the yellow/black location on the headlight relay and what I get is a holding circuit that won't turn off.....even with all switches off and the key removed, the headlights won't turn off until you unplug the wire. Put the key in, plug in the jumper wire-----headlights are still off-----advance key to the run position---lights are still off----- flick the parking light switch and all the lights come on. Now you can't turn them off. Flick the switch, remove the key, they're still on. I even tried a different fuze/location on the fuze box and it still happens. I tried this a buncha weeks ago when you guys gave me the info and the same thing happened. I thought I'd check out the wiring before I got us grasping at straws. I'm pretty sure things are right. Any ideas?

Very simple fix, drive it only in the daytime, you won't need headlights then

[thescifiguy]

That's essentially what I did, except I put a double terminal on one of the spade tips sticking out of the fuze box(where a grey w/red wire was) and then just simply ran a jumper wire from the extra new spade tip to the yellow/black wire location on the relay.

Hmmmm......does this only work if I remove the wire from the fuze block ENTIRELY and plug it into the relay???? But the wire is attached to the fuze box for a reason: to get power from the fuze box to feed that part of the parking circuit. Is the grey/red wire you removed and plugged into the relay getting it's power from the relay? If not, then shoudn't some of the parking lights go out?

[rsefczek]

no, everything seems to be working normally with all lights functional. there is a prior thread that i started when i was having problems and i asked for help troubleshooting. ron (namba) helped me figure out which wire to pull. i don't have my chart with me otherwise i could tell you which one you need to pull.

remember that the parking lights also receive power from the headlight relay when it's activated so pulling the wire doesn't affect their ability to light.

[thescifiguy]

Okay, tomorrow I'll unplug a grey/red wire from the appropriate fuse location and plug or extend it directly to the yellow/black wire's relay location.

[wrench459]

The yellow/black wire coming from the micro-switch to headlight relay is the B+ for the field coil with the ground side being the brown wire.

Which runs straight to ground.

Theres two ways to control the field either power or ground to light up the headlamps.