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Loose Ground or Ground fault on 1939 Cadillac LaSalle Coupe

Ground Fault/Loose Ground Wire on 1939 Cadillac LaSalle Coupe

I have been told by members of my local Cadillac LaSalle Club that I have a loose ground wire that is causing the following symptoms: 1) Headlights going dim three seconds after turning them on
2) Headlights flickering at a very low light output 3) When headlights turned on the instrument lights and key light go dim, flicker, and go out 3) Taillights also flicker when the headlights are turned on.
4) The battery charge gauge gyrates quickly between D (discharging) and C (charging).

When the headlights are not on, the instrument lights work and the taillights work fine. The battery charge gauge also stays dead center in the gauge and does not gyrate.

I read in the owners manual that when there is a ground fault that the Thermostat Relay will cause the headlights to flicker.

I spent the last several hours and was able to eliminate several things. The headlight grounds are not the problem. I removed the bulbs from the headlights, turned on the lights, and the instrument lights and taillights still flickered. I removed the floor switch, cleaned it, traced the ground wire and made sure it was well secured, then replaced the floor switch. The lights still flickered. Finally, I pulled the battery and made sure the ground wire to the frame was clean and well secured. Lights still flickered.

Finally, I crawled into the floor board and checked all the wiring that I could reach under the dash to make sure all connections were secure.

The headlights still flicker.

Does anyone have any suggestions?

John P. #31819

What about the ground wire for the generator?