Installing the Tekonsha Primus IQ # TK90160 on a 2005 Mercedes-Benz ML500

Question:

Have a Mercedes 05 ML500, What color wires are connected to under the dash?

asked by: Tom

Expert Reply:

I can help you with the installation of the Tekonsha Primus IQ # TK90160 on your 2005 Mercedes-Benz ML500 but unfortunately, I don't know which wires you will be splicing to under your dash. To figure out what wires you need to use simply take a circuit tester like part # PTW2993 and test the wires (there may be a bundle) under the driver's side dash. Look for a constant 12V of power, a wire that only gets hot when the brake pedal is pressed, a wire that outputs voltage to the 7-Way at the rear of your vehicle, and a ground wire. You will then need to connect the pigtail that comes with the Primus IQ to the following functions:

Blue - 7-Way Output to Trailer
Black - 12V Power
White - Ground
Red - COLD Side of Stop Light Switch (only gets hot when brake pedal is pressed)

expert reply by: Jon G