smparr

I was driving my '70 98 to work this morning and noticed my turn signals and high beam indicators were dimly lit, about 1/5 brightness while driving. They go out when the lights are off or when I'm parked with the lights on and slowly light up and get brighter as I drive but never more than 1/5-1/4 brightness. They all still operate correctly when used. I thought maybe the other lights were shining through them but when I'm parked with the lights on they are not lit. I'm thinking maybe a ground but what else should I look at?

Vintage Chief

I'd suspect the voltage regulator. Is your ALT an internal VR or external VR? Additionally, I'd start w/ the basics.
What is the voltage of your battery with car off? Should be ~12.6V
What is the voltage of your battery with the car running in the on position? Voltage should be ~13.9V - 14.6V. If you're over 15V that's an issue and if you're under 13.5V that's an issue.

smparr

External solid state replacement voltage regulator. I'll have to check the battery when I get home.

Sugar Bear

I'd suspect a ground connection that is loose or corroded is causing high resistance and creating a weak ground to the instrument cluster.

smparr

Update, battery voltage was good and I didn't find any loose grounds. Strangely the last drive I did for the season the issue wasn't there. Everything was normal. I guess I'll have to wait and see next time.

sysmg

There is a foam material that surrounds the idiot lights. It is there to prevent the gauge background lighting to bleed into the idiot lights. If you don't have the issue when the gauge lighting (parking light or headlight on position on the headlight switch), then it's likely the foam has deteriorated and the light is leaking through the missing foam seal and bleeding into the idiot light area.

smparr

Resurrecting my own old thread, the lights are doing it more. In fact now turning the lights on causes the fuel gauge to deflect left. Back to ground hunting I guess.

Vintage Chief

The fact this occurs w/ all lights lends itself to a faulting external solid state replacement VR.

Vintage Chief

After a quick re-read, I noted the fuel gauge is now deflecting. Good place to check ground connection is the fuel tank ground wire. Remove it and clean the metal where it attaches and the wire terminal end.

cjsdad

What is wrong, is what is new. I doubt the regulator would cause issues like that with your dash. Did you replace any turn signal or brake light bulbs? It sounds like you have a voltage feedback loop.

Did you replace the radio? The dash light wire often gets mistaken as a ground wire and can cause weird things to happen before the dash light fuse blows.

The fuel gauge thing could be a coincidence, or it may be a fault in the dash wiring causing everything. Either way, I would diagnose them as separate issues to start.

Just a couple thoughts.