Low voltage to brake controller '05 SD

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Dec 28, 2018 | 02:07 PM

bilter

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Mountain Pass

Joined: Aug 2003

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Low voltage to brake controller '05 SD

I just had the brakes on my enclosed trailer serviced. When I picked up the trailer I tried the brakes in the parking lot to make sure they worked. When they did not I went back in to ask if they had tested them, which they had. Sent a tech out who put the brake tester on the 7 pin plug on the truck. Had the integrated controller set on full gain and activated the brakes, only got 3 volts. It should be around 12 according to the tech. Has anybody run into this issue? I am thinking it is the control module but at just over $300 I want to be sure before spending the money.

Dec 28, 2018 | 03:14 PM

ifrythings

Fleet Mechanic

Joined: Aug 2011

Posts: 1,571

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I believe the early tbc required you to be moving 15-25mph before it would put out full current to your trailer.

Heres a bulliten about your issue TBC Bulliten

Dec 29, 2018 | 12:36 PM

bilter

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Mountain Pass

Joined: Aug 2003

Posts: 245

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yes, they did but I was previously able to lock up while not moving. Currently while moving 30+ mph, at full gain, I get only a light tug when I activate the brakes. Im thinking I'll either just risk the $300 (pretty sure it is the module) or just spend $50k on a new truck

Jan 14, 2019 | 02:19 PM

bilter

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Mountain Pass

Joined: Aug 2003

Posts: 245

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Ok, for anyone that may run into the same situation in the future I ended up making my own repairs to the brake control module. I removed it from the truck and dissembled it. I cleaned the slides with contact cleaner and inspected the circuit boards. On the small board at the front of the unit (right behind the display) I found a tiny crack in one of the solder joints. I applied more solder, reassembled and installed the unit. Brakes work like day one. Saved $315 by doing this.