Can the Rear 12 Volt Socket on a 2018 Volkswagen Golf be Used to Power a Trailer Light Harness

Published 11/29/2018

Question:

Would it be a problem if the +12 VDC power for the converter box is only hot when the ignition is on? i know that it would only power trailer lights when ignition is on of course. The car has auto headlights, so as long as the control switch is left in the auto position, the tails would only light when ignition is on anyway. I checked, brake lights are disabled when ignition is off. if the parking light position of the headlight switch or hazard flashers were engaged with ignition off, i know the trailer lights would not light, but would those conditions risk damage to the converter? i am preparing to pull a U-Haul trailer and when that task is complete i will remove the harness and the hitch. There is already 10A 12VDC power available in the rear compartment, only concern is it is switched with the ignition. i am trying to minimize modifications for the one-off task. i accept and understand the conditions the switched 12 VDC would impose. My only concern is inadvertent concerter damage. BTW Vehicle is s 2018 Volkswagen GTi Autobahn with factory LED tail lights. thanks for your assistance.

asked by: James

Helpful Expert Reply:

I really wish that I could tell you that the 12 volt power source you have in the rear compartment of your 2018 Volkswagen Golf is suitable for the Curt T-Connector Vehicle Wiring Harness part # C56405 but it is not. The keyed circuit is not the issue but rather the power draw of the harness. This harness requires a 15 amp fuse and as you mentioned the power source in your rear compartment is only 10 amps. Therefore, it is very likely that with multiple signals active like the running lights and turn signals you can exceed the circuit's capacity.

With that being said this is all rather a moot point as the manufacturer will not warranty the harness unless it is attached to the positive side of the vehicle's battery. If you were to change out the fuse for the rear compartment that would then void the warranty of your vehicle and it is simply not worth the extra time it takes to run the power wire to the battery.

I will say that running the power wire to the vehicle's battery is not going to cause any permanent modifications. If you need help with this I have attached a help article for you.

expert reply by: Conner L