Man, the wiring in these old cars really goes to sh*t as they age... My latest gremlin is that the ash try lamp wire that I was using to trigger the night time illumination dimmer on my gauges and stereo no long seems to be offering a solid signal. I tested the circuit and it seems to sit at about 3.6v even when the lights on the car are in the off position. This is causing my gauge to always run in dimmed mode I'm guessing a ground in the circuit is no longer providing a solid ground connection. I looked though the wiring manual and it looks like the culprit might be the "Panel lamp control switch" or it's related ground. The attached diagram shows the switch sitting somewhere around the radio, but I took a look and didn't actually find anything there (just below the rear of the radio). Anyone where exactly where this thing sits? Also it's not clear from the wiring diagram where it's ground wire actually connects to the chassis. Any insight into this? Thanks.

 

Sorry to speculate, but It's likely that it grounds directly to the dash bar. The dash bar does tend to oxidize, since it's not treated. Others who have painted and coated their dash bars have reported various electrical gremlins IIRC.