Break controller problems

[Farmer2750]

I have a 2004 Chevy 2500hd duramax with a Allison. I wired on a break controller because the one I bought it with did not work. I used a new plug and go harness on a Curt Discovery controller. I have power and ground to the controller but no numbers showing the true value of the breaking value and when I hooked up to our flat bed, brakes work tested on dads truck, I had no breaks. I've checked wires, fuses, anything I can think of. I even got a new controller but it is still doing the same thing. Any ideas at this point is appreciated!!

 

[Diamondpilot]

Are you sure you have it wired correctly? Most common issue I see in my shop is messed up wiring at the controller.

The colors on the controllers usually don't match the trucks. So what I'm saying is red wire doesn't always connect to the red wire, ect.

Follow the schematic or have a professional do it.

The other big issue I see on GM trucks is a bad 7 round plug at the back of the truck.


As for the trailer, is it a 6 round plug converted to a 7? If so 6 rounds have 2 ways of being wired. There is no single industry standard like with a 7 round.

Chris

 

[Stimw]

I have an 04 Silverado that came with tow package.
IIRC there was a wiring kit to connect the controller in the truck with instructions.
The kit also contained a fuse that needed to be installed under the hood in that large fuse block.
I have a cheapo Reese Controller from Walmart that works great with my 16' trailer loaded with about 6000 lbs.

 

[George2615]

If you have power and ground at the controller and it doesn't work that leaves the wire from the brake pedal switch to the controller or the blue wire that goes back to the trailer plug. One of them isn't working.
Like Chris said, it may be a problem at the 7 pin plug. Being an 04 I'd suspect the wiring in the plug could be corroded or broken and start there. Then check for continuity from the blue wire in the plug to the brake controller. Lastly, check the ground at the 7 pin plug.

 

[Farmer2750]

Well I solved the problem, like George and Chris said, I had serious corrosion problems in my plug(spaids were broke off) so a quick trip to Runnings for a new plug and wired that in and I'm back in business! Thank you guys for all your answers!