2002 Chevy Cavalier gauge backlight/dimmer

Tiny
MISCHAW
  • MEMBER
  • 2002 CHEVROLET CAVALIER
2002 Chevy Cavalier

I took my girlfriends dash apart to install a better looking mounting bracket for her aftermarket stereo. After I put the dash back together I realized that the instrument (gauge) panel LED lights are not turning or dimming using the dimmer switch. Pushing the dimmer switch all the way up still turns on the dome light, but the instrument panel remains dark. All of the gauges and warning lights work, just not the backlight. I've checked the wires on the gauge wiring harness as well as behind the switch an everything looks OK. I also checked the fuses. PLEASE HELP!
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Wednesday, December 24th, 2008 AT 9:38 PM

6 Replies

Tiny
BUDDYCRAIGG
  • EXPERT
Did it work before you took things apart?

Did you do any testing with a test light or multimeter?
Or just visually inspect things.

.

All of these items are on the same circuit.
So if they work, then something is unplugged.

Master window switch.
Radio illumination.
Instrument panel illumination.
HVAC control illumination.
Shift indicator illumination.
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Thursday, December 25th, 2008 AT 12:05 AM
Tiny
MISCHAW
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Yes, it worked before I took thing apart. Keep in mind that I'm not an electrician nor a mechanic. The only testing I did besides visual inspection was to remove the wires from the back of the dimmer switch. There were two sets of wires, I crossed one set and the dome light came on. I crossed the other set and nothing happened (I was hoping the dash would illuminate with full power)

All of the items on your list work, except for the Instrument Panel illumination. How does the control for this end up at the dimmer switch? It looks like the dimmer switch wires join into a larger bundle of wires inside the dash. Should I take more of the dash apart?

I found something online that said the illumination wire for the radio may be the culprit. Do you know what color it is? The radio wiring harness looks like it was installed using the cut and splice method, with plastic caps connecting the wires together. Also FYI, whoever installed the last radio wired it to work with the engine off, so I don' think its using the illumination function.
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Thursday, December 25th, 2008 AT 12:41 AM
Tiny
BUDDYCRAIGG
  • EXPERT
As a word of warning.
Car’s with computers don’t like to have wires crossed.
There isn’t much left on a car that doesn’t have the electricity run through a resistor or transistor or flux capacitor these days.
You can cause a lot of damage by crossing wires.

There is a GREY wire that comes out of the BCM.
It goes into the dash and somewhere close to the connector for the passenger air bag,
The GREY wire branches off in 5 or so different directions.
Sending power to all of the other light bulbs in the dash.

So if you have power at the GREY wire that plugs into the instrument cluster.
And have a good ground at the BLACK wire on the cluster.
Then all of the bulbs are burnt out, or there is a problem with the cluster.

Good luck
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Thursday, December 25th, 2008 AT 12:43 AM
Tiny
MISCHAW
  • MEMBER
Thanks for the insight, I'll remember not to cross any more wires ;). Unfortunately I don't have the equipment to test wires for power.

Do you know which wire in the radio harness is responsible for dimming? Should the HVAC control and shift indicator also dim?
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Thursday, December 25th, 2008 AT 1:02 AM
Tiny
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It looks like a gray wire also goes to the radio. I'm going to go poke around again in the car.
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Thursday, December 25th, 2008 AT 1:09 AM
Tiny
MISCHAW
  • MEMBER
Well, sometimes when you take a break the problem becomes easier or disappears - the latter in my case. I went to test if the dimmer worked on the HVAC and shift indicator and VIOLA the instrument gauges dimmed too.

Very strange. Thanks for the feedback! Donation is yours.
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Thursday, December 25th, 2008 AT 1:42 AM

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