How To Install a 7-Way Trailer Wiring Harness On a 2019 Subaru Ascent

Updated 09/26/2019 | Published 09/25/2019

Products Featured in This Question

Universal Installation Kit for Trailer Brake Controller - 7-Way RV and 4-Way Flat - 10 Gauge Wires

(3373)

$121.31

Tekonsha OEM Replacement Vehicle Wiring Harness with 7-Way Trailer Connector

(34)

$124.89

Tekonsha Plug-In Wiring Adapter for Electric Brake Controllers - Dual Plug In

(83)

$21.31

Wire Loom 1/4" Diameter, 10' Long

(292)

$8.15

Question:

Installed the following on the Ascent and using a Tekonsha P2 controller: 76253 Draw-Tite Max-Frame Trailer Hitch Receiver - Custom Fit - Class III - 2 C56040 Curt T-Connector Vehicle Wiring Harness 4-Pole Flat Trailer Connector ETBC7 Universal Installation Kit for Trailer Brake Controller - 7-Way 3062-P Tekonsha brake controller wiring harness Ive ran the 10 ga wire to the front of the vehicle. Just want to confirm the connections I reviewed the instructions for the ETBC7, but it appears to be for direct wiring the brake controller. - Black wire - connects to battery using the 40-amp breaker. Does this need to be covered somehow since its a hot wire? - White wire - Use the 20- or 30-amp breaker for Tekonsha controller? Since using the 3062-P, I assume this goes through the firewall and connects to the Blue wire on the brake controller harness and all other wires are connected through the plug?.

asked by: Mike

Expert Reply:

There are two different 7-way trailer wiring harnesses for a 2019 Subaru Ascent dependent on whether or not you have the factory tow package. If you do have the factory tow package then you should be using the Tekonsha OEM Replacement Vehicle Wiring Harness part # 118290, not the Universal Installation Kit for Trailer Brake Controller part # ETBC7. If you found a plug under the dash for the Tekonsha Plug-In Wiring Adapter for Electric Brake Controllers part # 3062-P then you have the factory tow package.

Therefore, if you have the factory tow package you don't need to run a wire from the trailer connector to the brake controller but you will need to run one from the trailer connector to the battery. If you don't have factory tow package then you will need to run both the black wire from the trailer connector to the vehicle's battery and the blue then white brake output wire up to the back of the brake controller. The black battery charge line circuit that runs from the trailer connector to the vehicle's battery does not need to covered but it would be a good idea to do so with some wire loom, part # 7509-10 will do the job though you may need two.

expert reply by: Conner L