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I just replaced the dash on my '74 GTV, and am working out a few electrical "issues" - but one has me scratching my head.

I read this topic enough to know that virtually all the gremlins living in my electrical system are caused by grounding problems.

But, the regular headlights (and other lights) work fine, no problems. Move the switch to high beams, and the parking lights all go out. I know it is a ground, but I was wondering if someone could recommend a place to start looking? My theoretical knowledge on how the switches are grounded is pretty weak - might it be something there? As I said, I just removed the dash, so I'm guessing it is inside the car, not up front.

My foglight relay needs to be replaced, too, but as far as I understand the systems run separately from one another.

thanks,
Chris
 

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I read this topic enough to know that virtually all the gremlins living in my electrical system are caused by grounding problems.
In general that is true. However, I'm wondering if your headlight switch might be the culprit on this one. Two questions:

- Do your tail lights and side markers, as well as your parking lights go off when you switch the headlights from L to H ?

- With the headlights on and switched to H, can you get the parking lights to flicker if you wiggle the headlight switch handle?

If just one parking light was going out, and that parking light and the corresponding headlight shared a ground connection, I could imagine how a poor ground could cause this. But, I don't think that is the case.
 

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That would be it. It is almost exactly as you said - tail lights and side markers, and I have been able to get them to stay on for a few seconds, but eventually they go out. Is this a fatal or repairable problem to the switch?

On a second note, I've got most everything hooked back up, and another (more serious?) gremlin has shown its head. As soon as I get the battery hooked up, the ALT light goes on (ignition not on). I turn on ignition, ALT light goes out, and the car starts and runs normally. I didn't change anything on the alternator or voltage regulator (that I noticed, anyway). Did I maybe hook something up backwards?

thanks-

Chris
 

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That would be it. It is almost exactly as you said - tail lights and side markers, and I have been able to get them to stay on for a few seconds, but eventually they go out. Is this a fatal or repairable problem to the switch?
Gee, it's nice to guess right every once in awhile. Well the switches can be repaired, but it's kind of like brain surgery. But your problem might be as simple as a dirty contact. And new light switches cost a fortune.

I have drilled out the rivets holding the two switch case halves together and taken them apart. However, be warned that it's like an explosion in a spring factory when you separate the case halves. And it takes four hands and 20 nimble fingers to hold all the internal bits back in place while reassembling the switch.

You might begin by spraying some contact cleaner into any holes in the switch, and hope it gets to the right spot. Seems like a long shot, but if I don't suggest it, someone else will.

On a second note, I've got most everything hooked back up, and another (more serious?) gremlin has shown its head. As soon as I get the battery hooked up, the ALT light goes on (ignition not on). I turn on ignition, ALT light goes out, and the car starts and runs normally. I didn't change anything on the alternator or voltage regulator (that I noticed, anyway). Did I maybe hook something up backwards?
Well something is hooked up incorrectly. The ALT light gets +12 from the ignition switch (same terminal as the coil and gauges) and is grounded at the voltage regulator. Once the engine is started, that point on the regulator goes to +12, and the light goes out. It sounds like the ground side of your light connected OK, but it's source of +12 is getting fed by a connection direct to the battery, instead of going through the ignition switch.

Generally the pink wires in the dash supply the switched +12 to the gauges and warning lights. So one leg of the ALT light should be pink.

I just looked at the top of this thread, and see that you have a '74 GTV - those cars have a printed circuit board in the gauge/light binnacle, and two rather flakey connectors that tie the PCB to the wiring harness. Hmm - some time with a mutimeter and wiring diagram may be in your future.
 
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