Removing the lighting gremlins

[peterro]

I'm getting close to having my car completed and back on the road. I've tested most of the electrical and it's pretty much working except for a couple items, which might be related.

The main issue is that the instrument cluster lighting won't come on. Headlights work but no dash lights. From looking at the diagrams, I believe the source power goes to the headlight switch with then feeds the dimmer. The dimmer in turn feeds the fuse block circuit for the instrument panel lights. From what I can tell, I never have power at the fuse. Without tearing the dash apart (again), I can view (with a drop cord, mirror, and aching back) that all the connectors are installed appropriately as they mostly can go on one way and have the proper colors.

I'm thinking that the dimmer switch may be dead but I won't know until I pull the switch panel and get some time with the multi-meter. Any thoughts on this?

The second issue is that the rear window defogger/fan only comes on when the headlights are on. This seems odd to me and I don't remember it working that way but it's possible. Is this normal or any thoughts on the fan/accessory wiring?

Thanks again.

[MEK-Dangerfield]

First off, I'll say all the original dimmers usually have gone the heaven by now, if your's wasn't rebuilt. That was a definite weak link in the circuit. I'll bet you put an Ohm meter between any two of the three prongs and you will read infinity(not good).


I have no knowledge of the rear window defogger.  Sorry.

[Chryco Psycho]

sounds like the power feed for the rear def is coming from the headlights this could be a problem with the dimmer as well possibly the power feed to the dimmer is in the wrong connector & the power source for the rear def should be constant

[peterro]

Thanks for the input. I'll have to pull the switch panel to gain access and test all the switches. From what I can see, all the connectors are on correctly as they can go on no other way. I guess the multi-meter will tell the story.