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2006 Silverado LT 1500
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26 Posts
Discussion Starter #1
I'm sorry if this sounds like a broken record with all the stuff that showed up on reverse lights not working in the search.

My problem is this... I bought the truck within the last two months and I'm not sure if the lights were working when I bought it or not. This is what I've found while trying to troubleshoot this problem, maybe someone can help me.

1) The fuse under the hood for the reverse lights is good and had power across it while the gear select lever is in Park and Reverse, but no other gears.
2) I do hear a relay snapping on/off in the dash somewhere when I remove and reinstall the fuse.
3) Both bulbs are good in the rear and with good grounds.
4) There is no power to the bulbs or the rear distribution block behind the bumper on the drivers' side.
5) The power wire to the rear distribution block for the reverse lights has a 300K ohm resistance to ground.

Can anyone tell me where the wire goes to further towards the front? It looks to me like it's a grounded wire, but I don't know where the wire comes from in the front area. Right now I have the truck up on ramps so I can look at stuff more in the morning if anyone has any ideas.

Thanks
 

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GMFS Member
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259 Posts
you should check the back up light switch, Im not 100% sure if on your truck it's on the transmission or the shifter lever, somebody else may be able to chime in on that...
 

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2006 Silverado LT 1500
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26 Posts
Discussion Starter #4
It sounds like you are referring to the Park/Neutral safety switch that is mounted on the side of the transmission. I did check that it was working, I checked for the voltage regarding the reverse lights and it does pass the 12V through to the BCM while only in reverse. All the other gears, including park only showed 0.7V on the multimeter. I'm hoping that replacing the BCM for the reverse lights will also fix the lack of dome lights, although it's weird since I'm getting voltage out of the pin, just really high resistance through the wire. lol Yes I know it won't fix the resistance but a man can wish lol.
 

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Registered
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2,078 Posts
I thought that switch was on the shifter on all automatics.
On all transmissions for trucks 1999+ the TCM, PNP/Reverse, and gear selector switch are on the case.
 

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4 Posts
Is it just the back up lights or do the rear brake lights not work also?

By chance is the vehicle set up to tow? The "t" that plugged into the rear wiring harness went bad on mine and when I took it out of the loop that fixed the problem for me. Not that different lights worked on the rear end at different time. So sometimes the brake lights worked. Other times it was just the back lights that were a ting weird.
 

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2006 Silverado LT 1500
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26 Posts
Discussion Starter #8
I finally figured out this problem. I had to replace the "TBC-2B (15A)" fuse in the interior fuse panel near the driver's left knee. When I checked the fuses the first time it still looked good, but when I looked at it again later when I was installing my Bully Dog I noticed that it was blown. Once I replaced it the dome and reverse lights both started working again.
 

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03 4x4 ext cab lon bed
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5 Posts
Thanks Guys. This site was a blessing. mos68x was dead on. i replaced this fuse and all my interior and back-up are working. The manual lists it as a "truck body controller"
 

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425 Posts
Still working on mine :-\ my reverse lights inop no power to bulbs bulbs are good has towing checked fuses but gonna triple check when I can.

Sent from my A500 using Tapatalk 2
 

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Shit Disturber
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1,964 Posts
Still working on mine :-\ my reverse lights inop no power to bulbs bulbs are good has towing checked fuses but gonna triple check when I can.

Sent from my A500 using Tapatalk 2
Did you check the "TBC-2B (15A)" fuse ? And the other general reverse light fuses?
 

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10 Posts
I have a very similar issue, no reverse lights. I bought the truck from a private seller. He had swapped it from a manual trans to an automatic. Reverse lights haven't worked since I have owned it, and I would like to get them working again.
My Neutral/Park Safety switch is under the steering wheel like a manual would be, instead of on the trans like an Auto.
There also seems to be an insulated copper wire running under the truck, all the way from the back, and he had it running up where the shifter is now on the floor. ..this wire is going nowhere. He had it taped off on the end.
3rd backup light doesn't work.. All other lights work fine. Fuses are all good. Lightbulbs are newly replaced.
 

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10 Posts
Update: I got curious as to what the copper wire was doing there. So I spliced a wire to the fuse box, and Voila! I had reverse lights... But with constant power
I went to the parts store and picked up a toggle switch, wired it up, now its a flip of a switch and I have reverse lights. (Thinking about wiring some truck bed LEDs the same way, now :iranmaybe:)
 

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I finally figured out this problem. I had to replace the "TBC-2B (15A)" fuse in the interior fuse panel near the driver's left knee. When I checked the fuses the first time it still looked good, but when I looked at it again later when I was installing my Bully Dog I noticed that it was blown. Once I replaced it the dome and reverse lights both started working again.
mos68x, thanks much for this info. Your solution worked on our '06 Silverado 3500. You saved me a bunch of time troubleshooting...
 
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