Dash lights keep going out

[grotflo]

Wondering if anyone’s had this problem. When I first start my car and turn on the headlights, the dash lights work fine. After about five minutes, they slowly get dimmer and then stay off. Just affects the gauge illumination - all the other lights (indicator, high beams, oil pressure, etc) work. What could be the cause of this? Even if I dim the lights all the way off and drive like that, after a few minutes they won’t light up. 

[Mike Self]

Presuming you've already checked the relevant fuse (check your fuse listing, it varies by year), I'd suspect the dimmer function that's part of your headlight switch.  They go bad after awhile, and since they heat up in use, it sounds as if it's opening the circuit as it heats.  Try rotating the headlight knob back and forth several times while the lights are on.  If they start working again, that's almost certainly your problem. 

 

Before replacing the switch, you might try removing it (you have to take the instrument cluster out to access the switch).  Connect an ohmeter across the instrument lights terminal and rotate the knob--see if the ohmeter reading smoothly goes from open circuit to near zero ohms.  That'll give you an indication of whether it's functioning or not.  Then clean the resistance coil in the switch with tuner cleaner or whatever electronics folks use to clean electronics these days.  

 

mike

[wegweiser]

Gauge lights are often (perhaps always?) on the same fuse as tail lights. Make sure those be working, too! I think Mike is correct, however. 

[grotflo]

Appreciate the advice, I figured the dimmer switch might be the culprit.  I'll try cleaning it and see if that fixes it.

[coloincaalpine RIP 2021]

+1 Mike,     It's probably the rheostat on the H/L switch.    Let me know if you need one.

dq