Installing Prodigy P2 Trailer Brake Controller # 90885 in 2011 Subaru Legacy Sedan

Question:

I have a 2011 Subaru legacy sedan, I can not get to the switch to wire the controller, can I run a separate wire from the stop lights to the red wire on controller, stop light switch has 4 to 5 cold wires not enough room to get to stop light switch. also what color wire on switch best to use Thanks

asked by: Marshall P

Helpful Expert Reply:

First, thank you for your recent purchases from etrailer.

I'd first suggest a cautionary check of your Legacy owner's manual to confirm its towing capacity. Not all versions of any given year and model vehicle will necessarily share the same capacities. Towing a vehicle safely means having enough engine power, transmission cooler capacity as well as braking performance. If your trailer is large enough to need electric brakes, you definitely want to make certain that the vehicle itself and its hitch have the required capacity to tow your trailer and its load.

There can indeed be several wires going to the brake switch. For example, a cruise-control circuit will also use this switch to tell the vehicle when to disengage the accelerator. Testing is the best method, using a device like # PTW2993. Wire color alone is not a reliable method of determining function.

I checked with my technical contact at Tekonsha, and he said that typically the brown/yellow wire is the correct one to use to tap into the brake signal, which will be spliced to the red input wire on the P2's harness.

The linked article and video may be helpful for the balance of your installation.

expert reply by: Adam R