Curt Trailer Wiring Harness Shows Constant Power

Updated 06/30/2015 | Published 06/27/2015

Products Featured in This Question

Curt T-Connector Vehicle Wiring Harness with 4-Pole Flat Trailer Connector

(281)

$59.63

T-One Vehicle Wiring Harness with 4-Pole Flat Trailer Connector

(402)

$63.51

Question:

Installed a Curt 56165 trailer harness and found it would not control the trailer lights. Checked the 4 pin plug with a voltmeter to show it is reading a constant 12 volts on all 3 pins without the lights on. I returned/replaced the kit and installed another with the same result. My understanding is that none of the control wiring should show any voltage with the car lights off? I need guidance on how to troubleshoot this issue or if it is a controller failure or faulty harness, return it again. Thank You

asked by: Mark

Helpful Expert Reply:

What you are describing seems to be common in some Curt trailer wiring harnesses that use a powered converter. If you were to pull the fuse out of the fuse holder it should not show power any more (with the vehicle on or off).

I would recommend going with the TowReady equivalent part # 118412. This harness is also compatible with your vehicle, and will install in the same manner. We have an installation video showing this harness being installed on a 2009 RAV4, click on the provided link.

expert reply by: Chris O