Need help with electrical oddity

This is about a 1971 LS5.

The problem only occures when the headlights are turned on. As I drive, the right turn signal indicator turns on and off in a erratic manner. When it is off, all lights work as they are supposed to work. However, when the right turn signal indicator(on the dash)is on, the right turn signals (front and rear) don't work at all.

Does anyone have a clue of where I should start looking?
Any help would be appreciated.

|UPDATED|11/26/2003 6:30:57 PM (AZT)|/UPDATED|

I'm looking at my 68-71 wiring diagram and going by what you described. Does the right turn signals work at all, lights on and off? With the light switch on, you are powering the marker light circuit. I would start with the right bulb assemblies. You may have a wire shorted, or maybe corroded. Clean it first and check the bulbs. I once had a car that had water in the assemble and when I turned on the lights, or used the turn signal I had all kind of problems. Hope this helps.

Thanks Bill for taking the time to look at the diagrams for me. The turn signal works fine when the headlights are off. The phenomenon only occurs when the headlights are on.
I will follow your advice and keep you abreast.

Also check your ground (S255 is the same for turn signal and headlights)

Merci Jérôme,

A lot of detail indeed. I am not sure the electrical diagrams of a 1980 are a copycat of those of a 1971; still, I think the ground is a good thing to check.
This was thanksgiving week end in the US and I had little time to work on this, but I will.

Merci encore,

Turn signal wiring diagrams for all GM from mid 60s through the late 80s is the same. This is why GM steering columns are the ones of choice for street rod conversions.

Don't apologize Jérôme,
Your English is good enough if not excellent.
English is not my first language either, so I do appreciate the effort.

Christian

This is a common problem on many cars, not just Corvettes. There is a bad ground connection at the turn signal, park light bulb, or the bulb is shorted.
With the park lights on, the bulb does not find a good ground and electric flows backwards through the turn signal section of the bulb. Now the turn signal cirucit is hot, so the indicator comes on. The indicator uses a very low amperage, so there is enough to light the bulb. The other bulbs do not light due to a higher amperage requirement. The turn signal bulb filiment reduces amperage enough that bulbs requiring higher amperage do not light up.
The bad ground can be in the harness commection, bulb, or socket.
I have seen people waste hours on this, but if you know where to look it is a fairly easy fix.

Ken Styer