electric brake help

[Roofer]

My electric brakes stopped working on my '02 2500HD. I have power on the red wire, but no power to the blue wire for the electric brakes. Is there supposed to be power to the blue wire? My prodigy controller just says "nc" all the time now and I have no brakes. I looked at the wires under the cab and can't see anything wrong. Anyone have this problem?? Or any suggestions what to check??

[Mark Rinker]

Stop by and see Scott or Glenn at Crystal Welding, hiway 81 between Rogers and Osseo. Those guys are the best. :) Tell them Mark Rinker sent you.

[tufcj]

The red wire should see power when the brake pedal is pushed. The white is ground, the black is +12V, the blue is power out to the trailer (only powered when the brake lights are on).

Verify your +12V and ground to the controller. Verify that the trailer has a good ground at the white wire on the plug (don't assume it's grounded thru the ball). 90% of all DC power problems come down to ground.

Bob
tufcj

[DmaxMaverick]

If you see any display, it is getting 12V+. If it is indicating NC when you step on the brake pedal, it is getting a brake signal 12V+. And, the ground works, obviously. NC (no connection) means it is not seeing the brake coils (electromagnets) at the other end. First, check the inline fuse from the controller (if it has one, some do) to the firewall connector, and the "trl" fuses in the underhood fusebox. Then, check the wires going to each brake axle from the trailer's harness. It is common to find the splices poorly crimped and/or corroded. If you have a short, the controller should show an OL (overload), so you should not be shorting.

The RV connectors are notorious for poor contact over time. Check both ends of the connector for corrosion and opened/bent contacts. If they are clean (clean them if not) and making good contact, grease them with dielectric grease (tune up grease) and try again. You can check for brake voltage signal (variable, according to controller output) at the blue wire, or 5 O'clock in the truck recepticle, or 7 O'clock looking at the back of it. If you get voltage when the pedal is pressed, look to the trailer for an open circuit. If no brake voltage, you have an open circuit between the connector and controller. Can't offer much help with that, it could be anywhere between.

[Roofer]

Thanks guys. I have a few things to check out now. It has to be on the truck because it happens with two different trailers.

Does anyone know where the blue wire is spliced? I can't see where it comes to the under hood fuse box.

All the lights work, but no trailer brakes. There has to be a short somewhere or something because it worked before, but not now.

[kaylabryn]

My memory is not so good but isn't the blue wire the brake control wire, you know the one the the voltage is variable depending on controller setting. If it is then the blue wire comes out under the dash and plugs into the brake controller. Someone please verify!!

[Turbo Al]

I put mine in myself but can't find the bloody schematics. The dark blue wire (thick one) comes out of the dash and is connected to the brake controller dark blue wire. Still looking for schematics LOL
AL

[DarylB]

Are you using the factory harness? I think it's got 6 wires and you use 5 (dont use the brown one)

I just swapped my controller from my 02 to the 07. They changed the position of the 12V "hot" wire in the harness on the 07 (I think it started in 03).

[joncar]

check fuse under hood in large fuse box..
check for 12v on pin at out put in the 7 pin connector under rear bumper..hope this helps...joncar

[NutNbutGMC]

My memory is not so good but isn't the blue wire the brake control wire, you know the one the the voltage is variable depending on controller setting. If it is then the blue wire comes out under the dash and plugs into the brake controller. Someone please verify!!

Wiring diagram at Tekonsha ==> http://www.tekonsha.com/instructions/BC%20Wiring.pdf

Wiring Harness chart ==> http://www.tekonsha.com/files/BC_Wire_Harness_Chart.pdf

Wiring Harness Bulletin for 2003 ==> http://www.tekonsha.com/files/Product%20Bulletin%20-%2020020013.pdf

[Roofer]

Okay, I've been busy lately, but I did check and I do have power to the rear plug on the blue wire with the brakes applied. Do I have a bad ground on the ball? Thing is that it happens with both the tag trailer and the gooseneck. Still says "NC" on the controller. Can the controller go bad? It didn't just all of a sudden stop working. At first it would work fine, then it would not work the next time I drove it and back and forth for a few times and now, it shows not connected all the time. Is there a fuse besides the maxi-fuse that controls the box? I would think if it was a fuse, I wouldn't have power at all. I just can't come to a decent conclusion. Thanks very much for the help so far.

[a5150nut]

Have you maybe broke the ground lead from the plug to frame/ground on the truck?

[JohnC]

... Do I have a bad ground on the ball? ...

You do have a separate ground in the harness, right?

.NC. simply means the controller doesn't see a good circuit from the blue wire through the brakes to ground (on the truck).

[Roofer]

I used my test light and attached the ground to the ground on the plug and the pointer on the positive and it lit up. This should mean the ground is working, right?

I'm really starting to think it is a fuse or a bad controller. I wish I had my old controller to swap it out and see.