Ground and Power Installation for Prodigy P3 # 90195 Brake Controller on 2017 Toyota Highlander

Question:

Hi, Just got a box from etrailer full of parts and a break controller for a 2017 Toyota Highlander. 2 questions. 1 The 7 conductor socket for has a white wire with a ring connector for a frame contact at the back of the car. Is it better to just solder on another section of wire and run all the white wires up to the negative battery post? 2 Under the dash, the break switch is really buried along with the wire which needs to be connected to the red wire on the controller. Back at the rear the rear break wire will be easy to get at. Any reason not to connect there and run 1 more red wire up front to the controller along with the power wires? I hate working on trailer wires.

asked by: Larry H

Helpful Expert Reply:

I took a look and noticed that you received the Prodigy P3 # 90195 brake controller as well as the T-One Wiring Harness # 118449, the Universal Wiring Kit # ETBC7, and 10 Gauge Wire # 10-1-1.

To answer your first question, although that would seem to be the better option, using that long of a ground wire could cause some issues on your circuits because it may be too long for the current to actually ground. If you are comfortable with soldering though it would be better to solder the ground connection as opposed to using the screw method. Just be sure that it is a clean, bare-metal surface.

As far as the red wire for the P3 goes, you can very well run a wire from a rear brake wire up to the brake controller. Just be sure that the wire you connect to only receives power when you press the brake pedal in your 2017 Toyota Highlander otherwise you will get some interesting braking from your trailer.

I have attached a installation videos and helpful articles that you can reference for the installation as well.