No dash lights, headlights only come on with dimmer

[Kenneth Barton]

I’m in the midst of refreshing some things in my dash. I got my passenger ash tray working for the first time ever apparently, evident by the factory defect tag. 

“While I’m in here I might as well replace some bulbs proactively.” That was a mistake. 

After replacing bulbs, nothing worked. I decided to clean the headlight switch - all the contacts with alcohol and a q tip.

Now I have no dash lights at all, and the headlights come on only when you rotate the dimmer all the way like you’re activating cabin lights. 

Theres no obvious wire breakages, and I’m suspecting the headlight switch since it’s responsible for power distribution. 

All fuses look good. 

Any ideas?

[Kurt]

That is strange. Did you replace with incandescent bulbs or LEDs? I've heard that some LEDs are not the correct polarity for these cars. Did the headlights work fine before you cleaned the switch? If you disassembled it, maybe something went wrong with the reassemble. My headlights were intermittent a while back. After I found out I could not find a new switch for under $500, I took mine apart & cleaned & lubed it. So far it's been working great.

[Russ Austin]

Troubleshooting is in order. The single gray wire on the headlight switch is the dash lights. The blue wire on the connector is the headlight power to the dimmer switch. Check that they have 12V

[Kenneth Barton]

Thank you both gents. I had the connector installed incorrectly - it was one blade too far over. Now headlights work as expected.

Still diagnosing dash lights. The single gray wire is getting 0.34v. The red, blue and green wires on the headlight switch are getting 12v when the headlights are on.

Next I’m going to clean up the fuse holders for the instrument lights.

[Kenneth Barton]

Touching both sides of the fuse with my meter yields 12.2v.

I’m afraid somehow there’s a breakage in the wires in between.

[Kenneth Barton]

So it seems that the gray wire is not getting power at the headlight switch, despite power being fed properly.

Everything looks good on the outside of the switch, but I’m going to attempt disassembly.

[Kenneth Barton]

Think I found the culprit - looks like a broken connection on the rheostat.

Studying the thing for a little bit lead me to this.