Connecting Ignition Switched Power From 2015 Toyota Prius v to Enclosed Trailer

Published 06/24/2019

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Question:

Isolation is half the solution, which connectors should I use between the vehicle and trailer? Option One - use the brake wire of a 5-pole flat using: VEHICLE: Adapter 4-Pole to 5-Pole Trailer Wiring Adapter - Shorter Item # 47515 TRAILER: 5-Flat Trailer End 48" Harness Item # 20017 Curt 4-Pole Flat Vehicle Wiring Harness w/ Mounting Bracket Item # C58345 Option 2 - use the proper pin on a 7 way with VEHICLE: Adapter 4 Pole to 7 Pole Vehicle End Trailer Connector Item # 30717 TRAILER: 7-Way Molded Trailer Wire Connector, 4' Long Item # H20043 Curt 4-Pole Flat Vehicle Wiring Harness w/ Mounting Bracket Item # C58345

asked by: Sheldon T

Expert Reply:

You will need to use a circuit tester like # PTW2979 to find a wire in your 2015 Toyota Prius v that is hot only when you use your key (ignition switched power). When you do that you can simply wire in the Battery Isolation Solenoid # PK5231201, which should be wired like in the accompanying diagram with 10 gauge wire # 10-1-1.

I have added a link to a video review of the solenoid for you to check out.

expert reply by: Kyle S

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Sheldon T.

6/24/2019

Kyle S.

6/24/2019

Both of the options you stated will actually work, however, I recommend going with option two, using the 4-way to 7-way Adapter # 30717 which you can mount with Brackets # 18138 and # C57202; you'll also need Circuit Breaker # PK54530 between your battery and Solenoid # TR118665. A 7-way is meant to run to a 12V battery so this is the best option. You can then wire your trailer with the 7-Way Molded Trailer Wire Connector # H20043.