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Electric Brake Controller for Trailers:

I just received a Reese Brakeman Digital, and I am wondering about the under-dash connections. I went digging around under the dash for the three wires specified in the service manual. I found these wires:

  • Yellow: Trailer Brake Controller Batt Feed (connected to a small black box - 30 amp - connector)
  • Blue: Trailer Brake Circut
  • Red: (no tag) ...but it looks like it goes to the brake pedal stoplight switch.

The Reese has four wires (blk, wht, blu, red) and specifies that the (+) and (-) be connected directly to the battery. Since the Hummer comes with this preexisting tow wiring, I'm assuming I should splice the (+) batt wire from the Reese to the yellow (batt feed) wire under the dash. Would this be correct?

The blue wires should match up.

The red wires should match up.

And it looks as though I should route a (-) ground wire directly to the battery.

Any insight would be greatly appreciated.

'95 gas wgn

Hey Bob

Do you have a pin out of the rear Berg connector and how you connected up your controller??

It would be much appreciated..!!


I switched out my original connector of seven round poles to a Ford plug of six flat poles and a large round center pole. The Ford plug is the current plug on the Hummer.


Today I battled trying to setup my controller on a '95 wagon with a trailer assembly person. Initially there was only power for turn signals. Getting out the fuse panel schematic, there was a 15 amp fuse missing (Probably from the factory since I am the original owner) that then provided power to the rear connector for batt power-, brake lights, parking lights, running lights--(sort of 2 of the same function here). A 25 amp fuse was also needed for the electric brake controller.

We used a Draw-tite controller which had a brake wire- blue, stoplight red, black-battery, ground-white. The blue wire went to the blue wire hanging under the dash, Red to red, the yellow under the dash went to black on controller + batt. A ground had to be spliced in.

After the controller was connected, no electric brake power.. Went to the manual under accessories-trailer and saw a section about cutting the preconnector wires -blue and purple and switching them-(real pain to do this in the tight space). There was a blank space in the block connector where one of the wires should have gone. I guess this is why AMG went to a different connector.

After that, the electric brake power was present and operated the brakes. We hooked the battery for the breakaway to the parking light as to not overcharge the battery. The full time power at the connector apparently is to provide domelight power to a camper. There was an additional brake light connector apparently for European application.

It took 4 hours @ 65/hour plus me searching the manual and help of several emails I received.. I figured it was not straight forward when several left out details, Bob swapped out the connector and another said to fish for wire in the engine compartment. In this setting it was good to have a guy who does this on a daily basis. Cuts the time way down.


See also this forum thread

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