texasbaehr

None of the Lights, signal indicators or hi beam indicators are working on my main inst cluster. Headlights and all ext. lights work fine. I pulled the unit, checked all the bulbs, cleaned all the connectors, have a good ground on the harness black wire. Still no lights. I have power to the Gauge Iluminator light circuit but its weak and cuts in and out when I use the dimmer. I will replace the light switch but this should not affect the turn indicators. I'm going blind trying to follow the wires on the wiring diagram.
I need to get the hi beam indicator to work to pass inspoection.
Any one have any ideas or other things I need to check.

SIXFOOTER

Maybe this will help

7T1vette

Either power (12vdc) or ground connection is not getting made in the circuit. That's the only way ALL of those lights would not be working.

texasbaehr

OK I found all the bulb sockets were oxidized, I cleaned them up and checked each one and re-installed , now the turn indicators, hi beam and choke lights work but no illumination. I am ordering a new light switch and a printed circuit, the PC is not in great shape.

rzkas

i have a similar problem. No center gauge light and no speedometer light. My signal light works and hand brake light. Can't see gauges at night. The light when i open the door works. Is there a fuse to check or what might be the problem.
I have a 82.

texasbaehr

I just spent all night troubleshooting this. The lights on my speedo, tach and center gauges are out, fuses are all good. Narrowed it down to the headlight switch. It has a dimmer in it for the dash lights, mine is shot and not getting power to the dash lights. A new switch is $35.

LannyL81

The dimmer in the headlight switch often breaks, which of course results in no current to the interior illuminatiion lights. So if all lights are not working, then it is the dimmer. But if some do work and some do not, then look for bad sockets and the flex circuit connectons.

Replacing the headlight switch is not too bad; pull the speedo/tack cluster out for access. Just be sure to get the vacuum lines reconnected correctly. And the new one will not come with the rod/****...will need to reuse existing one.

rzkas

i have replaced my headlight switch

texasbaehr

If the fuse is out your dome light, glove box light etc. would also be out. The only thing left to check is to see if you have power and ground to the PC on both gauge clusters. If you don't then you have a loose connection or dirty terminal in a connector. Also pull all the bulb sockets and make sure they are not oxidized. All of mine were and I had to fold up sand paper and clean them all out and bingo the lights worked. Electrical gremlins are a nightmare in these cars.

Trents77

I am having a similar problem with my 77. We have removed the dash, changed the headlight switch (the dimmer was broken, but replacing the switch did not help anything). We traced it down to the fuse box, and we used an electrical tester to see if there were any power coming from either side of the instrument lights fuse, and there wasn't. Do you know where I could be losing power? Every other fuse it all good accept the instrument lights.

texasbaehr

Thats strange that you have no power to the fuse terminals. I have never had the fuse block out so, I am not sure how it is constructed.
first thing to try is to make sure the fuse termianls are not corroded. oxidation is typical on those tin plated connectors. Use a peice of folded up sandpaper and slide it in between the terminals on the block to clean them then check for power again. You will unly get a positve reading on one side side ( the hot side) make sure you have a good ground for the neg side of your tester. If there is still no power then you may need to remove the fuse block as you may have a cracked buss or wire.
If all else fails start a new thread and see if someone else has dealt with this. I hate electrical gremlins.

milo30

I am having the opposite problem on my '81. When I turn on the headlights, all of my dummy lights in the center cluster light up. I got another printed circuit to see what it does but hadn't really thought about the headlight switch. I guess I need to check that too this week.

texasbaehr

Did you replace the center cluster PC?
Sounds like you have a cross between the gauge light pos. and the pos. side of the idiot lights. Make sure the connector fits properly in the PC and that the tabs on the PC for the connector are not folded over or creased. Also check the connector to make sure all the terminals are separated and not bridged with a piece of PC or broken tin.

milo30

Did you get yours fixed?

texasbaehr

My problem was a combination of oxidized connections on all the bulbs in the PC and the dimmer in the light switch. I cleaned all the bulb connections but ended up replacing the PC because the film was in bad shape. I cleaned the light switch with electrical contact cleaner and now everything works.

Trents77

I look on the wiering diagram and tracked the power source to the instrument fuse to a green wire comming from the headlight switch. We are going to test that wire for power tonight and see what needs to be done. We might have to replace the entire wire, which might not be too hard.

78 silver 78

Will electrical cleaner work on the bulb sockets ? Mine are some what oxidized. I was just going to replace all,but not at 3 bucks each. What is a good cleaner ?
Thanks