Hi guys, I have a 2002 GMC 3500 with trailer wiring and a MaxBrake controller. It worked after I installed the the controller, but after a while, there was no action.... The display is normal an lights up. It does not work either when I apply the manual override.. The pump runs when I detach the brakeaway pin. But I suspect it runs on the brake away battery only.... What to look for? The feed fuse is intact in the engine compartment fuse box.

Thanks!

Is it getting feedback from the brake line sensor?

They've been great to talk with when I installed mine. Might give MaxBrake a call

If it is on, you are getting power to it. The next check is if the wiring to the trailer (blue wire) is making contact to the brake unit itself. you can use a test light to check for voltage on the blue wire while someone holds the manual engage lever on the unit. Check wire coming out of unit, check splice where it is connected to truck harness. Check at plug in back of truck. Somewhere you have lost connection.

Rich

You have two fuses.. The 12V feed and the signal...

Since the pump runs, I'd expect the signal and feed are there, but the output may be the issue... Not enough 12V feed...., or a bad or somewhat bad ground...

Quickest thing to do is connect the truck to a different trailer...
You could have a brainboard issue w the pump.....

if everything lights and pump runs, was it originally a surge brake trailer? if so the reverse lock out solinoid is bad and not allowing the brakes to work. if so just bypass it as you dont need it for Elec over hydraulic...hope this helps.

There must be a problem somewhere in the truck. It does not work on any trailer...

The pump is entirely new, so I doubt there is a problem with that one.

I can find a large fues in the fuse box which is for trailer wiring. That is 30 or 50 A, and I guess that is the feed wiring. That is not blown.


I have one other veery strange thing with the controller..... When I drive in the dark and go from high beam to low beam, the controller lit up even it I don't haul a trailer! I guess this happened after I installed HID Xenon kits for both the high and low beam. How is that possible????

Thanx

Some of the EoH systems require a wiring adapter to work with the truck. It's sold by Myco.
www.mycotrailers.com

BUT, I don't see why you would need it with a MaxBrake controller. You may need to pin out each connection with a voltmeter.

I have HIDs on my current Ford truck and I also run a MaxBrake brake controller. No issues.

On my old 2002 Chevrolet Avalanche 2500 which had the same wiring setup as yours, I had a wire break in the wiring harness right at the trailer hitch, about 2" in front of the trailer connector. That whole setup you have on your truck is a poor design as many of them get knocked/bent by something you drive over. I solved that problem by moving the trailer wiring connector up to the bumper beside the license plate.

I get a new control module for my Brakerite II SD from Titan. They were very helpful.