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So I was driving back on the highway the other night and I turned my headlights on. Immediately the lights went out and my car refused to switch back to the low beams. I thought it was the switch in the steering column, so I replaced that. No difference. I checked the relays (I still get the click too) with a multimeter and everything seems fine on that front too (from what little I know about operating those), and the fuses are fine. So all I can think now is that there's an issue with the microswitch and I have to go dig it out, which I really don't care to do again. I've already replaced all the headlight wiring and that was no fun. Before I take the unwanted plunge and buy the microswitches does anyone with more experience than me have any ideas as to if it could be anything else?
 

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Opeler
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Simplified headlight wiring

:yup: See page 2 of attached files.

https://www.opelgt.com/forums/1c-li...4-simplified-headlight-wiring.html#post192065
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.

:ponder: Maybe needed?
https://www.opelgt.com/forums/1c-li...4-simplified-headlight-wiring.html#post199674
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?
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
 

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Is this a GT? The rotator microswitch only controls the headlight on/off relay, NOT the dimmer relay. And unless they have been added, there are no fuses in the headlight circuit, just the fusible links. It is a "good idea" to add a fuse, although I prefer a re-setting circuit breaker, so that an overload doesn't leave you in the dark.

The first suspect would be the problematic rubber insulated headlight wiring, but if that has been replaced from the butt connector to the headlights, hopefully that isn't the issue.

It sounds like either the headlight relay or dimmer relay isn't working properly, which is quite common. Pretty simple to check the output terminals for power. Do you have a schematic to refer to, that will show you which terminal on each relay should be energized? I don't have a schematic handy to suggest which terminals should be tested for power, but if you don't have a schematic, someone will likely chime in. Or I will later.

New relays are available from Opel GT Source, but you need to confirm that is the problem, and which relay if it is.

HTH.
 

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Bad Ground at Column /Fuse box

I had this problem with my Yellow GT. I flicked the headlight High Beams the stick wiper arm on the steering column , heard the relay click once
Then I could't turn them off, made a click again but did turn off..

So turns out the relay I believe latches closed. The problem Turn out that the steering column was improperly grounded.. had problems with the Horn button too.

The ground On the column goes though the harness to the stud nut on the fuse box. So I ran a new ground wire from the place where the grounding strap mounted in the engine bay and grounded fuse box stud and steering column ground wire

So Far High Beams working nicely last few years,, The High Beams were "'Really"" bright //when using the Hella H4 Bulbs too :yup:
No more intermittent high beam problem worked for me :)

There are also two ground wires on the driver side near the hood hinge going towards headlight buckets that are Headlight grounds check those screws make sure properly ground too.
 
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Discussion Starter #7
Is this a GT? The rotator microswitch only controls the headlight on/off relay, NOT the dimmer relay. And unless they have been added, there are no fuses in the headlight circuit, just the fusible links. It is a "good idea" to add a fuse, although I prefer a re-setting circuit breaker, so that an overload doesn't leave you in the dark.

The first suspect would be the problematic rubber insulated headlight wiring, but if that has been replaced from the butt connector to the headlights, hopefully that isn't the issue.

It sounds like either the headlight relay or dimmer relay isn't working properly, which is quite common. Pretty simple to check the output terminals for power. Do you have a schematic to refer to, that will show you which terminal on each relay should be energized? I don't have a schematic handy to suggest which terminals should be tested for power, but if you don't have a schematic, someone will likely chime in. Or I will later.

New relays are available from Opel GT Source, but you need to confirm that is the problem, and which relay if it is.

HTH.
Yeah, i'm not sure. It seems everything on the relays are getting power (except for the ground) both when the lights are "on" and when they're "off". Do you happen to know if that's supposed to be the case?
 

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If you’re getting 12vdc power on the #56 spade terminal on the headlamp dimmer relay (12 gage yellow wire) the problem would probably be under the hood between the headlights and that spade connection double check your ground wires at the headlights. You could try removing the yellow wire and jumping it out. If the lights come on something else might be dropping the relay out after the load is applied. It might just be a bad relay. If they don’t come on you might have more wiring to replace. Mine crumbled all the way back to the engine compartment. My halogens draw about 6 amps on the low beams (yellow wire) 10 amps on the high beams (white wire) when all is good. Start with the easy stuff and work back towards the micro switches last IMHO. Maybe I’m lucky but mine have never given me any trouble and I’ve pulled apart the headlight assembly a couple of times at least. It’s usually the wire connections, relays or wiring that has needed attention.
 

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Discussion Starter #9
Solved - Finally

Well after too long of the lights not working it was the dumbest problem it could have been. I'm just happy it's taken care of though. It simply ended up being a bad ground. But hey, at least I have brand new switches and relays now!
 

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I had this problem with my Yellow GT. I flicked the headlight High Beams the stick wiper arm on the steering column , heard the relay click once
Then I could't turn them off, made a click again but did turn off..

So turns out the relay I believe latches closed. The problem Turn out that the steering column was improperly grounded.. had problems with the Horn button too.

The ground On the column goes though the harness to the stud nut on the fuse box. So I ran a new ground wire from the place where the grounding strap mounted in the engine bay and grounded fuse box stud and steering column ground wire

So Far High Beams working nicely last few years,, The High Beams were "'Really"" bright //when using the Hella H4 Bulbs too :yup:
No more intermittent high beam problem worked for me :)

There are also two ground wires on the driver side near the hood hinge going towards headlight buckets that are Headlight grounds check those screws make sure properly ground too.
Well after too long of the lights not working it was the dumbest problem it could have been. I'm just happy it's taken care of though. It simply ended up being a bad ground. But hey, at least I have brand new switches and relays now!
Glad you got it fixed, Bad Grounds are a common problem. driver fender well, steering column, fuse box stud On the back of the dash there are lots of blade terminals for dash grounds too. between speedo and tach My solution was, run a ground from one of the engine strap ground to also help ground fusebox....... Where was your Bad Ground ???
 
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Glad you got it fixed, Bad Grounds are a common problem. driver fender well, steering column, fuse box stud On the back of the dash there are lots of blade terminals for dash grounds too. between speedo and tach My solution was, run a ground from one of the engine strap ground to also help ground fusebox....... Where was your Bad Ground ???
My solution was to run a dedicated ground to the Battery for everything,(literally) all the way to the taillights. My Gt is 49 years old, I kinda expect things to go wrong.:sigh: Jarrell
 

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I like your idea Mike and Jarrell about additional grounding. These cars are so notorious for bad grounding :yup: I'm going to add that to my list of restoration projects.
I think most can relate to your problem gtillman, replace parts only to discover it was a bad ground. At least you know the new parts should last awhile :yup:
 

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Opeler
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https://www.wiringspecialties.com/groundingkit.html
The Wiring Specialties Grounding Kit is used to tie all grounding points in your engine bay together for improved performance. The main section is 6 gauge and the branches are 10 gauge. Can be installed in many different positions for maximum flexibility. Can be used on any engine with or without our PRO Engine Harness. Looks great in the engine bay too!

Thought of fabricating something like this for Opel GT engine compartment with some long ground wires reaching out to interior, etc. grounds. Compared to a Nissan 240SX, Opel electrical system is more simplified/ basic. Good winter project.
 

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https://www.wiringspecialties.com/groundingkit.html
The Wiring Specialties Grounding Kit is used to tie all grounding points in your engine bay together for improved performance. The main section is 6 gauge and the branches are 10 gauge. Can be installed in many different positions for maximum flexibility. Can be used on any engine with or without our PRO Engine Harness. Looks great in the engine bay too!

Thought of fabricating something like this for Opel GT engine compartment with some long ground wires reaching out to interior, etc. grounds. Compared to a Nissan 240SX, Opel electrical system is more simplified/ basic. Good winter project.
I say you do it Lindsey,
And then put them out here for all to envy
Put me down for one when you have them ready:haha:
 
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