Dash Lights Stopped Lighting

Jolo

Jolo

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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.
 
Why not a bad headlight switch?
If you have a wiring diagram check the switch.
 
Could be, but the headlights work. I did not think to check the fuse. I’ll check fuse box
 
Two different circuits in the switch.
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Jolo said:
Could be, but the headlights work. I did not think to check the fuse. I’ll check fuse box
Click to expand...
Check your taillights.
Usually, when your dash lights go out, you blew the fuse for your taillights.
Thats the idiot light for the taillights, no dash lights.
 
Taillights working. 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.
 
Jolo said:
Taillights working. 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.
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Just for S&G, turn your headlight switch to the right.
I reread you post and the oil guage did that to my buddies 79 Firebird.
If you turned the dash lights off, the oil guage stopped working.
This was decades ago.
This is the first time since then of hearing about it.
Just a shot in the dark.
Good luck
 
New fuse no dash lights. I surrender to my mechanic
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thanks R. saw your post after my last. I did the test suggested by the 1978 Pontiac service manual and disconnected gauge at sensor and gauge pinned to the right Then dropped back to zero upon grounding. I will buy a cheap sensor and see if the gauge works. Turning the headlight dimmer to right does not impact dash lights or gauge. This car is really testing me.
 
Melsg5, I think you got it right. I played with the dimmer on the headlight switch. Normally, turning the headlight switch far left with a click, turns the dome off. When I clicked fully left, the dash lights turNed on (not sure about dome as it’s not currently installed). As I click and turn right the dash lights off and they stay off. So the dimmer/rheostat on the headlight switch does not affect the dash lights. i think the rheostat In the headlight switch is bad. Thanks much for the insight. Very helpful.
 
Glad to hear you found the cause
 
One last closing point. I looked up the led dash lights I purchased. They are not dimmable. So they are functioning properly. They actually turn on when you turn the headlight switch far left before clicking off the dome. Some leds are dimmable, these are not notwithstanding they are sold as dash bulb replacements. Thanks for all the assistance

Have a nice Memorial Day

joe
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What do they do if you try to dim them?
 
At the dimmest setting they are on. When I try to brighten them by turning headlight switch to the right, they immediately turn off
 
Jolo said:
At the dimmest setting they are on. When I try to brighten them by turning headlight switch to the right, they immediately turn off
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Think that description is backwards, voltage to dash lights increases as you turn knob counterclockwise, reduces voltage clockwise. So the LEDS require approximately 12 volts anything less they go out.
 
Turn to left (counter clockwise) leds lights just before the dome light click. Turn clockwise, leds immediately go out
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Yes that makes sense, they wont work with less than full voltage, they should have mentioned that on the site you purchased them from.
 
That’s ok I did not consider that most leds are not dimmable, but they advertised them as dash bulbs. I did test to see if they get hot and they run cool, so as long as I am doing no harm I am fine with it.

thanks for assisting, appreciate it. I tried to send a video but the file would not load; probably too large

thanks again

joe
 
Jolo said:
That’s ok I did not consider that most leds are not dimmable, but they advertised them as dash bulbs. I did test to see if they get hot and they run cool, so as long as I am doing no harm I am fine with it.

thanks for assisting, appreciate it. I tried to send a video but the file would not load; probably too large

thanks again

joe
Click to expand...
Yes, LED's need full power to run.
They stay cool, last longer, are brighter.
Down side, once you go under 12.1v, they do not work.
You must get the multicolored to "dim" and wire those up.
Yeah, those are fun installing in a car......sometimes.
 
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