Tips for Installing a Trailer Wiring Harness on a 2008 Mercedes R320

Updated 06/27/2016 | Published 06/25/2016

Question:

Hi, do you have instructions specific for a Mercedes R class? I dont seem to be able to find them. Thanks.

asked by: Santiago L

Helpful Expert Reply:

Trailer wiring harness # 119250KIT is a universal type of hardwire harness so it doesn't have vehicle specific instructions for any vehicle. Basically, all you would do is use the included circuit tester to probe the tail light wires on your 2008 Mercedes R320 and attach the harness' wires accordingly.

The yellow wire is left turn signal, red is brake lights, brown is running lights, and green is right turn signal. The remaining wire is the power wire that connects to the vehicle battery. But on your R320 the brake light signal is on the same wire as the turn signal wire. So, what you would do is ground the red wire with the white wire.

The # 119250KIT harness does note require splicing into your existing wires. Instead of splicing in this harness it has connectors that clamp around the wires to sense the electricity passing through them.

expert reply by: Michael H