Trailer Brake Controller Problem

I recently purchased an auto hauler and had a HOPPY brake controller installed by the trailer dealer. He hooked up the controller to the under-dash junction box. He just plugged in the after-market adapter into it.

Now here's the problem. I get a variable voltage from the controller if I adjust the thumb wheel on the controller. However, I get a constant 11.5 volts at the 7-pin trailer connecter when I step on the brakes. Darn near put me through the windshield. I was hauling a car from SC to MN at the time. It was more dangerous to run with the brakes on the trailer hooked up, so I disconnected the blue wire from the harness and just gave myself some extra stopping distance.

Is there a relay or something between the plug-in at the fuse box and the wiring at the rear of the truck? I assume my truck has the tow package standard as I have the tow button on the handle on the steering column. Of course I have pushed the button and do not get an indication light on the dash as I should.

Until I can figure out this problem, I am going to bypass the internal junction box and run an external (outside the firewall) blue wire from the controller directly to the 7-pin connector for the trailer.

Anyone else had this issue or know how to solve it?

Thanks.

Gary,
Sounds like a wire got crossed somewhere along the way. I found this site that might help.
http://www.etrailer.com/faq/cbc.asp