70 Cuda Rally Dash No Dash Lights

[kdcarman]

Hello,

I have no lights on the dash when the headlights are turned on.
The fuse is good.
The dimmer switch does turn on the dome light, but no dash lights.

Any thoughts?

[pschlosser]

grounding.  the dimmer switch relies heavily on the dash frame being well grounded.  otherwise, you may need to remove the dimmer switch to bench test.  the rheostat behind the dimmer knob is famous for oxidizing and failing to make a clean contact.  I began observing this after only 10 years of service.  rotating the knob fully left, then fully right, and repeating 20-30 times can often scrape enough carbon/oxidation off the coil to begin functioning again.  and if you do this with the headlights on in the darkness of a garage,  you can observe if there is ANY lighting function in the dash. often, you can see them flicker a little, encouraging the back and forth cleaning motion of the dimmer switch.

[kdcarman]

grounding.  the dimmer switch relies heavily on the dash frame being well grounded.  otherwise, you may need to remove the dimmer switch to bench test.  the rheostat behind the dimmer knob is famous for oxidizing and failing to make a clean contact.  I began observing this after only 10 years of service.  rotating the knob fully left, then fully right, and repeating 20-30 times can often scrape enough carbon/oxidation off the coil to begin functioning again.  and if you do this with the headlights on in the darkness of a garage,  you can observe if there is ANY lighting function in the dash. often, you can see them flicker a little, encouraging the back and forth cleaning motion of the dimmer switch.

Thanks for the feedback!

[kdcarman]

@ pschlosser

That did the trick.  Thanks!

[pschlosser]

suhweet !  no disassembly required.

[kdcarman]

suhweet !  no disassembly required.

I know, that was a big relief.