Brake Controller and Install Recommendation for a 2011 BMW 535i with Factory 7-Way

Question:

in addition to your brake controller what do I need. 2011 BMW 535i Sedan F10 I have the Invisahitch installed and all lights are working on trailer. They provided a module that taps into my BMW taillights etc. Their module does not provide the blue trailer brake wire but does tap into my BMW battery for charging and providing enough power for the trailer lights without loading the BMW tail lights. So my questions are: 1. Where does your controller get its brake light signal. 2. Since your controller does tap into my vehicles 12V, does it provide enough power to the blue brake wire out of the controller or do I need to add some relay?

asked by: John M

Expert Reply:

It sounds like you have a factory installed 7-way on your 2011 BMW 535i which means that to wire in the P3 # 90195 you would only need to power the controller with the power and ground to your vehicle battery, tap into the brake light switch and then run the output circuit from the controller to the 7-way. The power for the trailer's brakes will come from the controller which draws power from the vehicle battery.

For a wiring kit to install the brake controller and the 7-way adapter you would want the Wiring Kit for 2 and 4 Brake Electric Brake Controllers # 5506. This will provide the power source and ground for the wiring for the brake controller. You will need to test the wires from the brake pedal switch of your vehicle to find a circuit that has voltage when the brakes are applied and none when not applied. This will be the circuit you will run the red wire to.

Finally you will need to run a length of 10 gauge wire (part # 10-1-1) from the brake output circuit of the controller to the brake output circuit of the 7-way (blue wire). The # 10-1-1 is sold by the foot so you will need to order a quantity of the amount of feet you will need.

I attached an FAQ on installing brake controllers for you to check out.