Generation Specific => Second Generation 1970-1981 => Topic started by: Jolo on May 18, 2021, 05:40:39 PM
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On my 79 TA, the dash lights stopped lighting. High beam indicator and directional function but when I turn on the headlights, none of the gauges light. I tried adding a ground to no avail. Any ideas what has happened? I pulled the cluster out and tested every light. All are functioning. The bulbs are LED which I replaced a year ago and have been functioning Just fine. Really odd that my oil pressure gauge seems to be dead. Seems that it has to be a ground.
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Dash lights have a fuse on the fuse block. Don’t rely on a visual check. Test for continuity to be sure
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Are other dash cluster lights working? All on the same fuse, if other lights are working than its not the fuse. If you checked the grounds to the cluster the only other issue could be is a break in the printed circuit.
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Brand new printed circuit when I installed the leds last year. Could be fuse, because in addition to main cluster the heating/ac and the fuel and volt gauge are also out. Can’t believe i did not consider fuses. I’ll check.
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I agree its the fuse, also if I remember correctly the cluster had an additional fuse that is smaller than the other glass fuses. Hard to notice but you'll see it.
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Thanks, Yes tiny fuse. I pulled out the repair manual and it appears that is the one. Plus another normal size labeled gauges but that i believe is not the lamps but rather the gauges themselves. Having difficulty getting fuse out. Pontiac made nothing on this car easy to reach and service. Feels like it’s corroded in there. Probably never removed/replaced. My plastic fuse puller is not getting it out. I’ll try carefully with a small screwdriver tomorrow. Then I need to see the chiropractor.
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Always start with the fuses for anything weird, easier to check than pulling dashes apart, kinda...and doesn't hurt to remove and check or even replace fuse if it still looks good but haven't found the issue. It doesn't hurt to have a collection of new fuses on hand but especially some of the odd sizes like the short one. You can get special tools that make removing the glass fuses easier, many of the cheap plastic types simply do nothing. And, as you say, are probably half locked in place from years, add a smear of electrical grease to the tabs for next time, or refresh the lot while you have access, saves cleaning glass shards separately!
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Good advice, Thanks. I will get a better removal tool today. All the fuses seemed fused in place. I have continuity, but i still want to inspect the fuses. Maybe simply removing and installing new with electric grease will do it.
If I am unsuccessful, I will have my mechanic check it next week and report back. I am having it towed to him because despite setting timing at top dead center on compression stroke and distributor rotor at #1 plug, the car won’t start. Something is up; I have never had this issue with any previous cars.
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New fuse no dash lights. I will defer to my mechanic
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You may want to cycle the rheostat a time or two and see if you need to knock some rust off that. If not, I would bet you've just got a bad connection at a plug. Some of the time, I'll find that the light switch plugs have been overheated and damaged.
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Good advice checking switch, especially if someone has added more powerful headlights or upgraded to H4 without adjusting the wiring arrangement. Mine was melted accordingly, but patched up without changing the fault that caused it. Makes you question what the rest is like.
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Thanks to your last two suggestions, I uncovered the problem. I played with the dimmer on the headlight switch. Normally, turning the headlight switch far left with a click, turns the dome and dash lights off. When I click fully left, the dash lights turn on (not sure about dome as it’s not currently installed). Clicking to the right turns dash lights off and they stay off. So the dimmer/rheostat on the headlight switch does not affect the dash lights. This is odd except that I did install led dash lights that may be impacting the rheostat. Thoughts?
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Actually I think the rheostat on the headlight switch is bad. I think I need a new switch.
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Some LED bulbs are not dimmable. That may be your problem
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Some LED bulbs are not dimmable. That may be your problem
Oooo yea good point.
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Problem solved, or rather, there was no problem, just a new feature due to using LED dash lights.
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Another thing to be careful of with LEDs is the polarities, you have to match them.
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Correct, not dimmable. Thank you; all is good now thanks to your support
Happy Memorial Day to all
Joe