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Brake Light Conundrum - 2008 Colorado


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CptChadem
User

Feb 3, 2022, 10:21 AM

Post #1 of 20 (814 views)
Brake Light Conundrum - 2008 Colorado Sign In

Hello,

2008 Chevy Colorado Extended Cab - 4x4 3.7 L 5-cylinder, 4-speed auto

All three brake lights went out at the same time. So far I have tried the following:
  • Replacing fuse ("STOP" fuse), even tho it looked fine
  • Replacing bulbs
  • Replacing brake light switch at pedal
  • The brake light switch harness doesn't appear to have any voltage when I test it, so I figured the issue is somewhere between the switch and battery...
  • I get 12v on both sides of the fuse while it's in, with my black lead on the neg batt terminal, and the red lead on each side of the fuse (the exposed parts on top), as expected
  • It was recommended that I check the terminals for damage/corrosion, so I took the fuse panel off and checked the terminals, specifically where the STOP fuse is. All looked okay (nothing major observed; a bit of oxidation but it was all on another terminal altogether); hit them with some contact cleaner anyway.
  • Performed parasitic current test and doesn't appear to be any draw on that circuit with the car off etc., which makes it seem like it's not a short in the line which was my next best guess (thru this I did discover almost 1 amp draw from radio/OnStar which I'll need to address)
At this point, I'm at a loss. Any ideas? Maybe there is an issue with the wiring harness at the brake light switch? Or is there another component (like a computer) that the brake light switch communicates with that may be having issues? Or perhaps it could be another bad fuse somewhere? I checked all/most of the ones in the box under the hood already.

Side note: The battery is getting long in the tooth, but I doubt that's the cause otherwise I'd be seeing other issues which I'm not. It reads 12.4+v when truck is off.

Thanks ahead for any help at all.


(This post was edited by CptChadem on Feb 3, 2022, 10:27 AM)


Tom Greenleaf
Ultimate Carjunky / Moderator
Tom Greenleaf profile image

Feb 3, 2022, 12:53 PM

Post #2 of 20 (764 views)
Re: Brake Light Conundrum - 2008 Colorado Sign In

*Would be ridiculous if all bulbs were bad but have you proven zero power + ground to even one when it should light?
*The corrosion you found was minimal can mean it's nasty somewhere else just FYI.
*Switch new may not mean it's fixed right there again you need to see it light up power wires when pedal pushed.
Last for now is if this has trailer wiring factory or rigged in to tow see if that's intact or a mess now it could interfere with the whole show IDK for sure but it's a place for problems always wet if wet + hard to seal up nice touched or untouched since new,


T
(edit in) neat trick for bulb testing out of sockets) Try a 9V household battery with clip wires so you don't have to run all over the place for the truck's power. Use bulb grease again just anyway....



(This post was edited by Tom Greenleaf on Feb 3, 2022, 12:55 PM)


Hammer Time
Ultimate Carjunky / Moderator
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Feb 3, 2022, 1:38 PM

Post #3 of 20 (755 views)
Re: Brake Light Conundrum - 2008 Colorado Sign In

There is a direct line circuit from the fuse to the switch and then the switch to the brake lights. If you have no power on the orange wire going into the brake switch, then you either have a fuse problem or the wiring between the fuse and the switch.



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We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.



CptChadem
User

Feb 3, 2022, 6:12 PM

Post #4 of 20 (743 views)
Re: Brake Light Conundrum - 2008 Colorado Sign In

That's correct, no power at the orange wire at the switch. Tested this by placing my red lead in the connector, and then my black to a ground point on the body. I tested my methods here with another switch next to it for cruise control, which gave me 12v. So definitely no power at the connector for the switch, which rules out a problem with the switch or an issue beyond that, like the trailer brake wiring etc. (that was our first thought too since it does have the trailer light wiring; luckily it was all factory installed tho).
At this point, my best guess is that it's an issue within the fuse box, as opposed to a short somewhere between the fuse box and the switch which seems unlikely (although possible). I may just order a used fuse junction box and pop it in since I see some online for $115. The one in there now is pretty filthy and has seen better days.

Thoughts? And thanks for your replies; really appreciate the help.


Hammer Time
Ultimate Carjunky / Moderator
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Feb 3, 2022, 6:17 PM

Post #5 of 20 (741 views)
Re: Brake Light Conundrum - 2008 Colorado Sign In

You don't even understand what a short is. Definitely not a short unless that fuse is blown.

You need to test that fuse properly. Test at both ends of the fuse with the test light. It has contact openings on the top.






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We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.



(This post was edited by Hammer Time on Feb 3, 2022, 6:20 PM)


CptChadem
User

Feb 3, 2022, 6:33 PM

Post #6 of 20 (733 views)
Re: Brake Light Conundrum - 2008 Colorado Sign In

I've already tested the fuse at both sides with a multimeter, 12v each side. My red lead on each opening and the black lead on the battery terminal. I stated this in my OP.


(This post was edited by CptChadem on Feb 3, 2022, 6:37 PM)


Hammer Time
Ultimate Carjunky / Moderator
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Feb 3, 2022, 6:36 PM

Post #7 of 20 (727 views)
Re: Brake Light Conundrum - 2008 Colorado Sign In

OK, then you need to flip the box over and find the orange wire going out and see if it has power. It's pin #A11.



~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.



CptChadem
User

Feb 3, 2022, 6:38 PM

Post #8 of 20 (723 views)
Re: Brake Light Conundrum - 2008 Colorado Sign In

Ok, that's where I got kind of stuck. I got it out and found the terminal. How exactly do I test this? Should I place my lead into the terminal A11 and black to battery? I did that and I'm getting 0v

Edit: I tried the above on a few other terminals and some of them do show 11-ish volts so I'm assuming I'm doing it right but please confirm (and yes, I know the battery needs to be charged; in fact it needs to be replaced probably)


(This post was edited by CptChadem on Feb 3, 2022, 6:40 PM)


Hammer Time
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Feb 3, 2022, 6:42 PM

Post #9 of 20 (713 views)
Re: Brake Light Conundrum - 2008 Colorado Sign In

First make sure you have the correct wire. I gave you the plug and pin number. There could be more than one orange wire. Backprobe the socket using a paper clip or pin.

If it's a modular plug, unplug it and plug it back in. Could be a bad pin contact.



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We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.



(This post was edited by Hammer Time on Feb 3, 2022, 6:43 PM)


CptChadem
User

Feb 3, 2022, 6:46 PM

Post #10 of 20 (707 views)
Re: Brake Light Conundrum - 2008 Colorado Sign In

Pretty sure it is the right one based on the terminal diagram I have for X7, but I'll double-check. By back probe, do you mean just stick the clip up through the bottom where the orange wire enters the harness? And then put my red lead on that, as opposed to going in from the top of the harness/connector?

I don't think it's modular but not entirely sure what that means. I'll take a closer look to see if it looks like the wire will easily come out. It seems like the wires just go into the connector and won't easily come out

edit: for clarity


(This post was edited by CptChadem on Feb 3, 2022, 6:49 PM)


CptChadem
User

Feb 3, 2022, 6:49 PM

Post #11 of 20 (700 views)
Re: Brake Light Conundrum - 2008 Colorado Sign In

Here's a link to a pic of the terminal A11, if I'm correct: https://imgur.com/a/UT5m0ks


Hammer Time
Ultimate Carjunky / Moderator
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Feb 3, 2022, 6:53 PM

Post #12 of 20 (698 views)
Re: Brake Light Conundrum - 2008 Colorado Sign In

Modular means removeable plug. Some are hard wired. Do not try to remove the wire.
Just stick the pin in through the back and touch your light to it.

Here is the layout of the plug





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We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.



Hammer Time
Ultimate Carjunky / Moderator
Hammer Time profile image

Feb 3, 2022, 6:55 PM

Post #13 of 20 (696 views)
Re: Brake Light Conundrum - 2008 Colorado Sign In

Yes, it looks like you have the right pin but it all has to be connected when you test it.



~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.



CptChadem
User

Feb 3, 2022, 6:59 PM

Post #14 of 20 (690 views)
Re: Brake Light Conundrum - 2008 Colorado Sign In

Hah, that just dawned on me. Unfortunately that's going to be a royal pain I think with the way this is all set up, but I'll give it my best.


CptChadem
User

Feb 3, 2022, 7:01 PM

Post #15 of 20 (686 views)
Re: Brake Light Conundrum - 2008 Colorado Sign In

Is it okay to test it with only that one connector connected (X7) and the others disconnected? That will make it a lot easier to get something in there.


Hammer Time
Ultimate Carjunky / Moderator
Hammer Time profile image

Feb 3, 2022, 7:03 PM

Post #16 of 20 (682 views)
Re: Brake Light Conundrum - 2008 Colorado Sign In

No, one of them may be the power coming into the box. It has to be all together.



~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.



CptChadem
User

Feb 3, 2022, 7:04 PM

Post #17 of 20 (678 views)
Re: Brake Light Conundrum - 2008 Colorado Sign In

Ah, makes sense. Ok will try, thanks


CptChadem
User

Feb 3, 2022, 7:27 PM

Post #18 of 20 (671 views)
Re: Brake Light Conundrum - 2008 Colorado Sign In

I tried my best to get it all put back together with the backprobe wire in place and I just don't think I can make it happen. At this point I'm going to hope the open is somewhere in the fuse box and just swap it out. If that doesn't do it then I'll take it in somewhere because I'm already in above my head.

Thanks for the help and info. I've learned a thing or two in this, at least.


CptChadem
User

Feb 22, 2022, 11:43 AM

Post #19 of 20 (460 views)
Re: Brake Light Conundrum - 2008 Colorado Sign In

Just a final update for anyone who may read this. I found a used fuse box at a local pick-n-pull for $100 and that did the trick. So the issue was between the fuse and the terminal, i.e. somewhere inside the many layers of that box. I suppose it may have been repairable to someone with more electrical know-how, but I wasn't going there.


Hammer Time
Ultimate Carjunky / Moderator
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Feb 22, 2022, 12:00 PM

Post #20 of 20 (457 views)
Re: Brake Light Conundrum - 2008 Colorado Sign In

That's the way I would have gone after the diagnosis was confirmed. You lucked out with the gamble.



~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.







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