Adding a Brake Controller to a 2012 Mercedes-Benz Sprinter with 7-Way Trailer Connector

Updated 04/07/2017 | Published 04/06/2017

Products Featured in This Question

Wiring Kit for 2, 4, 6, and 8 Brake Electric Trailer Brake Controllers

(164)

$54.84

Roadmaster Stop Light Switch Kit

(659)

$48.79

Question:

The dealer told me that my Sprint is not pr-wired for a brake controller. What do I need. I have a tow package with 7 pin round plug. I would like instructions for wiring and installation. Note: This 7pin plug is controlled when power load is supplied when connected.

asked by: John

Expert Reply:

Since your 2012 Mercedes Sprinter does not have the wiring to plug in a brake controller but does have a 7-Way trailer connector you will need to do a little hardwiring to install a controller such as # 90195.

You will need installation kit # 5506. From the kit you will use the wire, 30 amp circuit breaker, and ring terminals. On the brake controller the white wire will ground to the negative battery terminal. The black wire will connect to the positive terminal via the 30 amp circuit breaker. The blue wire will attach to the back of the 7-Way connector in the 7 o'clock position. If there is already a wire there just remove it and put the wire you ran in its place.

The red wire is supposed to go to the cold side of the brake switch. But because it is buried in the vehicle somewhere and not practical to access you can instead use stop light switch kit # RM-751475. Basically it will wire to the vehicle battery positive post using its red wire and the green wire will go to the brake controller red wire. The switch is positioned behind the brake pedal so that when you press the brakes power is sent to the controller so it knows you are stepping on the brakes.

I have included several links that will help with this installation.

expert reply by: Michael H