Brake Controller Quit Working On 2005 GMC Sierra 2500HD

Question

Question:

my brake controller is not receiving power. it was and then was intermitant and now is doesnt light up att all. all my trailer lights work, but the brakes do not. like i said, the controller was working then stopped. all fuses are good under the hoodand the connection under the dash is good. i even replaced 7 way plug on trailer, nothing happened. the controller used to have a constant green on when the trailer is hooked up, but now has nothing. is there a different fuse or something else that is going on? thanks in advance. love the web site 2005 gmc 2500hd

asked by: Joe

0

Expert Reply:

I would check the power distribution box under the hood of your 2005 GMC Sierra 2500HD . The box is located under the hood and on the inside of the drivers side fender. Remove the cover, and locate the two auxiliary power posts on the inboard side of the box.

The post closest to the rear of the vehicle should have a red wire attached to it. Next to this post in the fuse box there should be a green 30 amp fuse installed. If the fuse is not installed or is blown, or this red wire is not attached, the brake controller will not get power.

There is another fuse you will want to check that is in the power distribution box. It is a fuse for the center high mount stop light (CHMSL). The diagram on the lid of the cover will show the fuse location. If it is blown it will not allow the brake controller to work.

Using a circuit tester like part # PTW2993, I would also recommend testing the wires under your dash that are connected to the brake controller. The black wire should have power all the time, the red wire only when the brake pedal is pressed, the blue wire should show power when the manual switch on the brake controller is turned on and when the brake pedal is pressed. I am including a video link of how to test the wiring on your brake controller.

Also, I am including a link to a FAQ page on GMC brake controllers that will show pictures and describe everything about installing a brake controller in your vehicle.

expert reply by: Jeff D

0

Steve S.

7/26/2020

I checked the wiring under the dash going to my trailer brake controller. And they al show a signal as they should, but the blue wire was a week signal.Any ideas about why that would be?

Reply

Chris R.

7/30/2020

It depends how you were testing that blue wire. That's the brake output circuit, so if you're testing it by stepping on the brake pedal and the truck/trailer is parked, it's not going to send back much power at all because the controller (assuming it's proportional) sends power back based on deceleration. Now if you're using the manual override on the controller and the voltage is still weak, that may be an issue. If that's the case make sure you have the settings bumped up on the controller itself and then test it again to see if it gets better. Let me know what you find.

Reply

Answer 1

On a 2005 Chevy Silverado 1500, If you are facing the front of the truck looking at the power distribution box, there will be a post at the back left side and a fuse slot near it. It is that fuse slot that you will install a 30 amp fuse. I have…

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Answer 2

Where are you testing for voltage on the blue wire at? If it is at the back of the 7-way then most likely there is a short on this wire that runs up to the brake controller and it would be best to replace it with part #10-1-1. However, if you are…

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Answer 3

It sounds like you will need to make some connections under the hood to make everything fully functional and get power to the brake controller. Wiring harness #3015-P is correct for your 2005 Chevy Silverado and it sounds like you have all the wires…

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Answer 4

Let's begin by making sure you have the controller wired to the GM brake controller pigtail correctly. The red pigtail wire connects to the black brake controller wire The light blue pigtail wire connects to the red brake controller wire The…

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Answer 5

I am not entirely sure what process you took so I'll give you some other things to try, or maybe a different way to test the Prodigy P3 #90195. First, sever the blue wire a couple inches from the back of your controller. Then use a circuit tester…

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Answer 6

In the Underhood fuse box of your 2008 GMC Sierra 2500 you will want to check the following fuses: 1- Right Trailer Stop/Turn Lamp 3- Left Trailer Stop/Turn Lamp 6- Trailer Brake Controller 10- Trailer Back-up Lamps 25- Trailer Park Lamps You can use…

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Answer 7

To isolate the brake light signal on your 2019 Chevy Silverado 2500HD you just need the Pacer Performance 3rd Brake Light Logic Module #PP20-702. You can use the attached installation instructions for the 3rd brake light on your camper shell.

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Answer 8

The main trailer wiring harness is located under the truck bed, usually above the spare tire. There is usually a socket for your trailer connector to plug into, but if you peel back the wire loom you will find a light blue wire further up in the…

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Answer 9

First, make sure that your #3015-P harness is pinned out correctly. The red wire should be in the bottom left location (if looking at the back of the end that plugs into the truck). Directly next to the red wire should be the blue wire. Above the…

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Answer 10

I do not know which controller brand and model you have or which wring adapter you're using. But for reference I linked our range of controllers, such as the Prodigy P3 #90195, confirmed to work with the 2005 Sierra with factory 7-way. This…

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Answer 11

The issue is the red wire of yoru brake controller. It's only supposed to see voltage when the brakes are applied which then tells the P3 #90195 to start looking for deceleration and apply proportional braking power. If there is a short on this…

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Answer 12

The Tekonsha P3 Brake Controller, item #90195, has built in troubleshooting diagnostics that you can access by pressing the menu button then selecting help and pressing ok. You will then be able to monitor the battery voltage supplied to the unit,…

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Brake Controller Quit Working On 2005 GMC Sierra 2500HD

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