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2005 Colorado Xtreme
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Discussion Starter · #1 ·
The gauges on my 2005 Xtreme have been stuck on dim since I bought it 5 months ago. The dimmer knob does not change brightness at the gauges or elsewhere in the interior (HVAC lighting, for example). I bought a new headlight switch/knob, but it made no difference, so I returned it, cleaned up my old one, and reinstalled it. Sometimes the lighting in the gauges goes off completely, although the PRNDL display never goes out. The bulbs in the driver's window switches are burned out, and a few in the HVAC are out, while the others in the HVAC sometimes flicker when first coming on.

So far I tried the new headlight switch as mentioned above, and cleaning the grounds on the driver and passenger inner fenders under the hood. I also took out the BCM and re-soldered around 50 of the larger contacts on it, but it honestly looks fine. No blown capacitors or burn marks. None of this has made any difference so far.

The truck has an aftermarket head unit, so some electrical wiring could be badly done. I also replaced a bit of wiring for the HVAC, which had melted the harness by the blower motor. I put in a new sub harness, resistor, and blower. About the only thing I did not check was a ground under the center console, which someone mentioned. I've heard that replacing the BCM could fix such issues, but I am reluctant to throw such an expensive part at a problem, when it may not even be bad.

Any suggestions? Could the issue be the gauges themselves?
 

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I don't think it's the gauges. I had a similar problem. It would go completely dark at random, the dimmer wouldn't work, and other times it would work just fine.

I redid the grounds on both sides of the hood and I can't say for sure that it fixed it, but it made it happen less often. Then one day everything just started working fine. It's been a few years since it has happened last and all is fine.
 

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The gauges on my 2005 Xtreme have been stuck on dim since I bought it 5 months ago. The dimmer knob does not change brightness at the gauges or elsewhere in the interior (HVAC lighting, for example). I bought a new headlight switch/knob, but it made no difference, so I returned it, cleaned up my old one, and reinstalled it. Sometimes the lighting in the gauges goes off completely, although the PRNDL display never goes out. The bulbs in the driver's window switches are burned out, and a few in the HVAC are out, while the others in the HVAC sometimes flicker when first coming on.

So far I tried the new headlight switch as mentioned above, and cleaning the grounds on the driver and passenger inner fenders under the hood. I also took out the BCM and re-soldered around 50 of the larger contacts on it, but it honestly looks fine. No blown capacitors or burn marks. None of this has made any difference so far.

The truck has an aftermarket head unit, so some electrical wiring could be badly done. I also replaced a bit of wiring for the HVAC, which had melted the harness by the blower motor. I put in a new sub harness, resistor, and blower. About the only thing I did not check was a ground under the center console, which someone mentioned. I've heard that replacing the BCM could fix such issues, but I am reluctant to throw such an expensive part at a problem, when it may not even be bad.

Any suggestions? Could the issue be the gauges themselves?
You could open up the ground splice box that is located in the engine compartment behind the air cleaner case. If you look closely you will see two tabs that lock the case parts together. Check for corrosion and insure that all of the wires are connected and secure. If I remember correctly, the terminals inside the box can be removed for cleaning. That is the ground point for the dimming circuit, but I don't know which terminal. PM sent.
 

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Discussion Starter · #5 ·
I took another crack at it today, and at first, no luck--but I THINK I HAVE FINALLY SOLVED IT! I read that there is a ground under the center console. I removed both front seats, which is pretty much necessary to get the console out (did some carpet cleaning while I had all that out of the way). There may be grounds under the seats and console, but only if they are under the carpet, and I wasn't about to rip that out as well.

I put all that back, and decided to attack the "ground splice box" at the passenger front inner fender by the airbox as per cart7881 above. I found this thread, which is a pretty good reference, including pictures. I wasn't able to get it open, but I did spray some battery terminal cleaner into it from the bottom, and pushed in all the wires with some pliers. I had already sanded down the fender to make this contact solid, so not much was really improved. The gauge lighting was the same when tested.

I opted to open up the headlight switch again. I had already cleaned all the contacts last time, and bent the spring contacts outwards, so there was not much to change. I wiped off a little of the dielectric grease, and I opened the dimmer knob again. This time I spent a good 5+ minutes making sure the spring contacts were perfectly centered along the "rainbow swipes". I reinstalled it, and for the first time, the dimmer actually dims all the lighting in the truck!

I suspect that it may have been 2 issues, like a bad switch/knob, plus a bad ground. Since I tried the new knob first, the ground may have still been bad. Once I put my original back, I guess I didn't do a perfect job refurbishing it the first time, which led to the gauges cutting out in addition to the flicker and absence of dimmer control before. The replacement switch (new, but aftermarket) could also have been faulty.

They aren't as bright as I would have expected, even at full brightness, but that is probably just the nature of the design, since the numbers appear black during the day. I may swap in LEDs at some future point. Hopefully, since the flicker/blackout was intermittent before, this keeps working reliably. I have confidence that it will. Thank you to everyone for your help!
 
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