How to Convert a 4-way Trailer Connector on a 2019 Subaru Ascent to a 5-way

Question:

I am looking at purchasing a Subaru Ascent. I have a trailer with surge brakes and a 5 pin flat connector. Subaru says the Ascent comes standard with the following, includes a live working 4 pin connector for brake lights to work, and a 7 pin electric trailer brake controller wire wire only from dash to hitch. Note: it does not have an electric brake controller so youll have to add an aftermarket electric trailer brake controller for the 7 pin wire to work.inch Does this mean that I can use a 7 pin to 5 pin flat adapter? Or will I have to hunt down a back up light wire, tap into it and replace the 4 pin connector? As far as I can tell, no vehicles come equipped standard with 5 pin flat connectors for surge brakes. Is this correct?

asked by: Gary F

Expert Reply:

The 4-pole to 5-pole adapter part # 20036 is the best way to adapt the 4-way on the Subaru Ascent to the 5-pin connector on the trailer but it does require you to splice into the reverse light wire. The reverse light circuit signals the lockout on the brake actuator while backing up the trailer, so the surge brakes do not activate. The blue wire on the adapter splices into the reverse light circuit on the Subaru

The reverse light wire is normally located behind the taillights of the vehicle. You can remove one of the outer taillights of the Ascent and test the wires with a circuit tester such as part # PTW2993 for the reverse function. Have someone sit in the driver's seat, pull the emergency brake and shift the car into reverse while you test. Once you find the reverse wire you can splice the blue wire from the adapter into it using the quick splice wire connector that is included with the adapter.

A brake controller is not needed with surge brakes because hydraulic brakes actuate with the help of the hydraulic brake actuator coupler. I have attached an installation video of the adapter on a 2009 Nissan Xterra. It shows the installer take off the taillights and find the reverse wire.

expert reply by: Heather A