Instrument cluster lighting issues

[Paul B]

I've got a 1981 C10 truck. All the backlighting for the instrument cluster was working fine. Booked the truck in to have a trailer brake controller installed and now I have no back light on my dash. The backlight on my heater control panel and my aftermarket tach are working fine with the headlight switch so I know I have power to there and that it's working correctly. All gauges on the cluster are working fine as well.

The part that has me puzzled is that while my turn signals are working fine the lights on the cluster are not lighting up any more as well. I'm thinking there's a common ground they share that got bumped loose or something along those lines. Either that or the board on the back of the cluster has decided to pick today to pack it in.

Ideas?

 

[Backfoot100]

Pretty sure that the lamp for the heater/AC control panel and the radio doesn't run through the dimmer of the headlight switch. That said, is the dimmer on the headlight switch turned off? It should be at the brightest setting just before it clicks the dome lights come on (if you have dome lights). Turned all the way opposite from that would have the inst. panel lights off completely.

 

[eskimomann209]

Don’t quote me. but I think they isnt cluster lighting has its own fuse. Were those checked?

 

[Backfoot100]

Don’t quote me. but I think they isnt cluster lighting has its own fuse. Were those checked?

I believe you're correct on that. Good call on checking it. Especially after someone was installing a trailer brake controller.

 

[Backfoot100]

Pretty sure that the lamp for the heater/AC control panel and the radio doesn't run through the dimmer of the headlight switch. That said, is the dimmer on the headlight switch turned off? It should be at the brightest setting just before it clicks the dome lights come on (if you have dome lights). Turned all the way opposite from that would have the inst. panel lights off completely.

I stand corrected. I checked my Sub last night and the climate control panel and Radio both dim with the headlight switch just like the rest of the panel lights.

 

[Paul B]

So I"ve checked fuses, all good, the thing that gets me is I've lost the flashing lights on the dash for the turn signals as well. Turn signals are working properly, all other lighting is working properly. I checked the ground coming from the instrument cluster and it appears to be fine. I'll have to pull the instrument cluster again and double check that they didn't pull it and get one of the connection's on the printed board folded over or something stupid, check it for any burnt sections as well. I'm starting to think that it's in the cluster itself. I've just replaced the headlight switch as well about a month ago, dimmer was working fine at the time I replaced it,

 

[Super-Dave]

I had a similar issue after someone else "worked" on my '73. A lot of weird "working" "not working" combinations with the lights, turn signals, flashers, etc...

Ended up being a poorly reconnected ground wire.