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I’m finishing my upholstery job on my C3 L82 1979. and after returning the dash back to it’s place I’ve noticed my instrument cluster and gauges lights don’t work.
Blinker indicators work fine.
Brake indicator light in dash works fine
Long beam indicator light works fine
On headlight switch tested, both red and green wire have 14.4V
All fuses are good, tested with multimeter
Tach/speedo connector unpluged and tested between black and gray wire, both good, they show 14.4V when touched together with multimeter
Dome light works
Brake and headlights work
…and I don’t get how the power is transfered from dash lights to gauges lights (those above radio)?!
I just picked up an 81 Corvette and the lights for the instrument cluster and gauges do not work. I plan to pull the cluster out and replace the light bulbs, these are typically small 194 bulbs and i figure this is the easiest starting point. After I check mine out I may have more information to share. But I am interested if anyone else has some information from past experience.
2025 c3 ('74-'82) of the Year Finalist - Unmodified
2019 C3 of Year Finalist (appearance mods)
Re check the fuses.
Originally Posted by CubeBrick
So, I don’t get how the power is transferred from dash lights to gauges lights (those above radio)?! Any clues?
The GAUGES fuse powers up the gauges.
The TAIL Light fuse sends power to the INSTRUMENT fuse.
The INSTRUMENT fuse sends power to the bulbs.
Check both sides of those fuses.
If only the instrument fuse blows, only the dash lights will be off.
If the tail light blows, both the TL and INS will not have power.
The center guage cluster has a printed circuit that the connector plugs onto in the rear. This printed circuit is flexible and easily damaged. I would start by carefully examining this printed circuit particularly at the point the connector plugs into it. Making certain all the contacts are clean on the connector side. And all the copper strip's on the printed circuit board are also clean and undamaged. With a bit of dielectric grease on the connector, carefully plug it back into the board confirming good contact with the copper strip's of the printed circuit.
The instrument lamp fuse should have power on both sides with the headlights on
This could be the culprit… If I remember correctly with headlights on only left side of the fuse had power. My logic was that when you install the fuse in it transmits power to the right side.
All fuses are OK and not blown btw. Also on the headlights switch with headlights on, orange wire did not have the power.
This could be the culprit… If I remember correctly with headlights on only left side of the fuse had power. My logic was that when you install the fuse in it transmits power to the right side.
All fuses are OK and not blown btw. Also on the headlights switch with headlights on, orange wire did not have the power.
did you twist the **** for dimming bulbs?
could be rheostat?
did you twist the **** for dimming bulbs?
could be rheostat?
Yes and there is 14.4V tested on rheostat wire, switch is new, but tested it anyway.
Also if I’m reading correctly I made a mistake while testing on the INSTRUMENT connector. I tested between power for the gauges and opposite ground which from what I can see on the board is only for brake light. I have to test on the same side top wire which is tach ground. That one runs all the way around the bulbs. But tach works so I guess it will come back as good ground.
Last edited by CubeBrick; Feb 17, 2024 at 10:25 PM.
This could be the culprit… If I remember correctly with headlights on only left side of the fuse had power. My logic was that when you install the fuse in it transmits power to the right side.
All fuses are OK and not blown btw. Also on the headlights switch with headlights on, orange wire did not have the power.
The orange wire gets power from the tail light fuse. It should have power all the time even with the headlights off and key off. That might be blown fuse or have a bad connection on the fuse.
The orange wire gets power from the tail light fuse. It should have power all the time even with the headlights off and key off. That might be blown fuse or have a bad connection on the fuse.
Ok but the tail light fuse is fine. So that would mean whatever source there is to that fuse it is not under power. Do you maybe know where tail light fuse gets the power from?
Ok but the tail light fuse is fine. So that would mean whatever source there is to that fuse it is not under power. Do you maybe know where tail light fuse gets the power from?
Check if the tail lights come on. It comes from the same source as the dome lights which you said works.
There is nothing wrong wit the orange wire, it has power. Tail lights work, gauges also work. Tested the connector, all wires have power, both grounds are fine. Ran my hand on the back side of the printed board though and it feels like dry grass, I was even left with small plastic particles with copper in hand. Guess that is it, I need a new printed board for the instruments.
Instrument cluster lights don’t work
