I'm having a really strange problem with my instrument panel lights that I thought I had fixed and was getting ready to button everything back up and it happened again.
The center console lights work fine.

The main instrument panel lights do not turn on - except for the high beam indicator light which comes on even with the high beam switch disconnected.

What's more unusual is that if I plug the high beam switch back in, the high beam indicator light will be on when the lights are actually on low and will be off when they are on high. (main instrument lights will still be off though)

Once in a great while before I took everything apart, everything would work. The dash lights would come on and the high beam indicator would operate as it should but the only happened twice in three years that I remember. Then I pulled that dash out and started cleaning up all the wiring (which was a mess) but none of the wire controlling these lights seem to be involved in the mess of hacked wiring. I had the instrument lights consistently working and then today, it went back to the way it was.

Maybe a new headlight switch?

Could be a short somewhere but I can't find it.

Any thoughts would be appreciated. I'm still reading through various related posts but can't find anything so far.

Thanks.

Eric

 

forgot to mention the year - its a 1978

 

Define "cleaning up all the wiring."

 

what I mean by cleaning up the wiring is:
previous owner had put in an aftermarket stereo and speakers but the power antenna did not work and I had a lot of high pitched interference sometimes (flip the fan switch, it goes away for awhile, then just flip the fan switch again, repeat as necessary). plus wires under the dash were always hanging just above my feet so I wanted to neaten things up and get the antenna working. I got the antenna working but am not sure about the interference yet. I also repaired my clock while I was at it.

There are vampire taps everywhere and connectors that go nowhere and really poorly done butt connectors so I am reconnecting what I can and trying to figure out what goes where. Everything pretty much worked except for what I described so I don't want to mess too much with what was working.

Also, I found that there's a light in the center console above the vents and I'm missing the socket for it so I'll order a new one. In fact, I'm wondering if that light is related to my dash light problem because things worked well until I plugged that connector back in then they went out. I though maybe I blew the fuse so I checked continuity in the fuse and it was fine and as soon as I was done checking that, the lights worked again for a short time. This made me think maybe its a fuse panel issue but if the center console lights and the driver instrument cluster lights are controlled by the same fuse, that wouldn't be it because the center console is working fine.

I found that at some point the courtesy light delay had been bypassed (thanks to this site I learned that) and that was a bad connection so I fixed that. If fact, I can't even find the relay that was bypassed - it must have been completely removed.

I was trying to find a 1978 fuse panel diagram as well but I've not gotten back to searching for that online yet and its not in either of my two manuals.

I said I was ready to button everything back up but only really just because its spring and I want to start driving the car again - I still have some connections to deal with that have bare wires and I really wanted to get this dash light problem worked out but I can live with only having the center console lights - I've lived with it for three years now.

So that's a long story for what cleaning up wiring means.

 

it seems to be the instrument cluster circuit board having a broken circuit path on the ground circuit. I'll either try a re-repair or have to replace it. I had it fixed once but I guess the fix was not good enough and that's why it worked for awhile. Probably best just replace it which seems easy aside from getting the circuit board out from beneath the tach contacts which seems like that will be tricky. Hopefully not.