Does anybody know if the circuit board of the instrument cluster is wired in series? The entire left side of my cluster (seat belt, Fuel Gauge, oil pressure) has no lights, up to the left side of the speedo. The right side glows just fine. I replaced two of the three bulbs on the left side but didn’t have a third to replace all of them. Just curious if anybody knows the answer. I’m kind of assuming the circuit board might have shorted out on one side, but fingers crossed it just needs the 3rd bulb changed to complete the circuit. Dimmer works just fine. All gauge lights working from the center of the speedo going right to the voltage and temp gauges.

 

The seatbelt light won't light if you don't have the warning buzzer module. Does it buzz for five seconds when you turn the key to the Run position? Does the turn signal indicator flash on the left?
There are only two bulbs for illumination, a left and a right. The rest are for brake and seatbelt warning, turn signal indicators, and the high beam indicator. (Did I miss any?)

If a good bulb fails to illuminate, you need to check the contacts on the bulb holder. Usually you can bend out those little prongs which contact the printed circuit board, and that'll fix it. Those prongs remember being held down for forty years, and they need persuasion to get back up. Plus maybe the cluster shell shrinks back some from the heat cycles, becoming slightly thinner around the bulb hole?

And if you're using LEDs, if one doesn't illuminate, flip it 180º, as they only work with + to + and - to -. Polarity sensitive. Diodes only pass current in one direction, like an electrical check valve.

 

No buzzing noise at all, so that would explain why there is no light for the seatbelt warning. Left turn signal does work, high beam switch is frozen in place so I really couldn't say if that indicator is working as of yet. Sounds like that third bulb in from the right (looking at back of cluster panel) might be my illuminating light. I will try replacing that bulb and go from there with the contact points if necessary. Thanks so much for the reply!

 

That brake light warning light module with integral buzzer would be up under the dash on the left side, near the hazard and turn signal flashers. Up behind the light and wiper switches.
You might be able to rejuvenate the high beam switch with some PB blaster or WD40 or something like that, if it's not too far gone. Acetone and ATF mixed 50/50 might do the trick too.

 

I want to say 7 bulbs in the cluster? Outers are indicators (seat belt and brake), middles blinkee, inners lightee, and top middle is high beam.

The seat belt buzzer is tucked up sorta behind the top of the EBrake pedal bracket, twist-locks into the kick panel. Mine all quit buzzing many years ago, but the light comes on for a few seconds on a key cycle......I think, can't say I look at it much.

I'd say also try swapping the seat belt bulb, socket and all - the socket contacts can be a problem, as can the whole white part of the bezel turning to dust - the first place mine went was around the high-beam socket, that's why mine doesn't work.......

Dimmer switches are cheap to replace, as I remember - it was a common stock part, I believe, used by everybody.......

 

Full panel is lit up! The socket itself was a bit chewed up so we swapped it with the one from the seatbelt indicator until I can find an extra. Now on to the high beams and buzzer, and whole list of other small projects. I appreciate the responses as well! You all are a wealth of information!

 

You may be better off just replacing the circuit board and IVR. I did this to mine and ALL my gauges went back to normal