Interior switch light relay?
 

Hi all,

Its a '83 MB 300D.

My interior switch lights (temp control, defrost, sunroof, etc.) do not illuminate when I turn my headlights on. I've replaced the single bulb connected to the fiber for these controls but the problem persists.

Does the power for these control lights/bulb go thru a relay (that might be bad)?

Any other ideas?

JWJ

Rotate the dash light rheostat back and forth until it works again.

I wish it was that easy.
 

Pete,

Its not the lights for the RPM, temp, and speed gauages.

Its the lights for the AC, defrost, and window buttons that are the problem.

The rheostat has nothing to do with them from what I understand.

Please correct me if I'm mistaken.

Thanks

OK, now MAYBE I understand. I think those lights work off a different contact off the headlight switch. Best to consult a schematic for your particular model, then check for continuity at the pertinent switch contact. Also, the ground wiring sort of daisy-chains from one bulb socket to the next, try bringing one socket ground contact "down to earth" and see if the other bulbs light.

The dimmer will dim all the lights in the dash, climate control included.