Trailer Lights Stay On When 2016 Ram Promaster 2500 Ignition Is Off

Updated 05/16/2019 | Published 05/15/2019

Products Featured in This Question

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

(54)

$91.73

Hook Probe Circuit Tester

(65)

$12.94

Question:

Hello my trailer hitch 4 pin the lights wont turn off when vehicle is turned off they stay on ? is that a relay ? 2016 ram promaster 2500

asked by: Jeff B

Expert Reply:

The Curt Wiring Harness part # C56270 is designed to fit 2015-2019 Ram ProMaster City. Since you have a 2016 Ram ProMaster 2500 you want Curt T-connector part # C56209. I was not able to find any relays that are related to the function of trailer lights so I do not believe that is the issue here. Usually if a relay or fuse is missing under the hood or in the power distribution box then you would not have power to the trailer lights at all.

If you have the correct T-connector and your trailer lights are still staying on when the ProMaster is turned off, then you may have a short in the wiring. Turn the vehicle off and test the circuits on the 4-way with a circuit tester like part # PTW2993. The 4-way should not be getting power to any of the circuits when the vehicle is off. If one of the circuits is getting power, then check the wire for frays or exposed wiring. The 4-way may need to be replaced if it's damaged.

You may also want to check that the black wire is connected properly to the positive side of the battery. If the black wire is connected to any other power source the 4-way may not operate properly.

If the trailer lights are LED lights then they take very little draw to power them. If they are LED lights and the vehicle is turned off you may see some of the lights illuminate very little. If this is what's happening you may have to disconnect the trailer from the towed vehicle when you are not towing in this case.

expert reply by: Heather A