LLY: Tapping Into Factory Dimmer

paint94979

Beer Nazi
Sep 18, 2006
11,715
8
38
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Im installing some gauges tomorrow and I wanted to know if anyone had a DIY or a few pictures as to what wire I need to tap into and how to do it? Thanks
 

2500HeavyDuty

Book 'em, Danno!
Feb 14, 2008
2,209
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Katy, Tx
www.myspace.com
when i first wired my gauges i got my power source for my gauges directly from the dimer switch, worked fine with 2 gauges on there, no problems at all. the dimmed with the dash lights.

I just popped off the panel where the gauges are and just used a 12v light tester to find the power out from the dimmer.

i don't do that anymore though, i just run a relay and a switch to turn the lights on and off.
 

RENODMAX

Dead Wrong
Mar 4, 2008
3,602
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On the LB7 its the brown and white wire leaving the dimmer switch. Take apart the dash and pop the dimmer out then take apart the loom to expose the wires. You can test to make sure with a voltmeter by turning your parking lights on and rolling the dimmer up and down. The meter will rise and fall if you have the right one... hope that helps ya:hug:
on edit: mines been this way for about a year and a half with no trouble whatsoever.
 

Bluemax

???????????
Sep 25, 2006
846
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Missouri
The dimming technique GM uses for the dash will work for bulbs AND LEDs. (PWM)


This is true, but I have the Cobalt C2 that are LED and when hooked to the factory dimmer they are still WAY to bright. ( And I mean like turn the interior of the truck blue bright, and I run my gauges pretty low anyways:D) I have mine hooked to the headlight switch on the brown wire and also have the auto meter dimmer on it as well. They have worked fine for almost three years now.:)
 

Bersaglieri

New member
Dec 28, 2013
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they made a major change in the wiring system in the 03+ models, mine is the dark green wire 99-02 silverado

Grave digging here, but maybe it's worth a shot.

Wired the lights for my two ISSPRO gauges to the dark green wire and everything seemed to work fine. Gauges lit up and dimmed along with the dash lights. Next day it got dark and both the gauges and the dash have no illumination. I checked some fuses, but they all seem good. Is there something I'm missing here?

2002 Dmax, 324,000 miles, EFI live, everything else stock.
 

Stancedlb7

Cummin Stroke this Duramax
Feb 9, 2015
649
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SLC, UTAH
Not sure if you got it fixed? But you might have burned up your switch. Get it changed out and use a relay.
 

Bersaglieri

New member
Dec 28, 2013
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Bought a new switch and it works now. I guess if it burns out again I'll have to wire it somewhere else. May have been unrelated.