Brake Controller and Install Wiring Recommendation for a 2011 Mercedes Benz GL 450

Question:

Hello, I have a Mercedes GL450 2011 with a tow package from the factory. I need to get a brake controller and the exact wire that goes from the controller to the under dash connector. Can you send me a recommendation? Im towing a car on a flat trailer in 8 days.

asked by: Chris R

Expert Reply:

For a brake controller I recommend the Prodigy P2 Brake Controller part # 90885. This is our best selling brake controller because of how well it works and how easy it is to setup. This is a proportional brake controller that senses the amount of braking the tow vehicle is applying and applies a proportionate amount to the trailer brakes.

To find the correct wire to use for the stoplight switch wire (red wire), of the brake controller you will need to use a circuit tester like part # PTW2993 to test the wires that run to the brake pedal switch of the vehicle to find the one that has voltage only when the brakes are on and none when released.

You said you have the tow package, but if you don't have a 4-way connector you would need to start with the part # 119250KIT and then use # ETBC7 to convert the 4-way to a 7-way and install the brake controller. There isn't a custom fit adapter wire for your vehicle for installing a brake controller, that is why you will have to hardwire the controller.

expert reply by: Jameson C