Troubleshooting Trailer Wiring Harness that Illuminates All Taillights on Trailer When Conncected

Updated 04/27/2015 | Published 04/25/2015

Products Featured in This Question

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

(23)

$53.85

Hook Probe Circuit Tester

(66)

$14.40

Question:

Got a Curt Upgraded Circ Prot Taillight Converter W/hardwire Kit from you guys about 10 months ago unit has stopped working correctly all lights stay on all the time no matter what when the fuse is in i have gone over the wiring and cannot find a reason for this i have used a multimeter to go over the wiring on the input side and everything is in line with what the vehicle signals indicate,

asked by: Ryan T

Expert Reply:

It sounds like the converter box of the Curt wiring harness you bought has shorted out.

What you will want to do is test the wires going into the box of the converter box for voltage with a circuit tester like the # PTW2993 to see if there is voltage going into the box when the taillight functions of your vehicle are applied, and then test the output side of the box to see if the current is making it through the converter. If not then the problem is that the converter box has shorted itself out and would need to be replaced.

Before you replace it you will want to inspect the wiring of your trailer to see if you can find anything that would cause the box to short out like corrosion or cut/exposed wiring. These boxes don't usually go out unless there is a short on the trailer that takes it out.

If there isn't input voltage for the converter then the problem is the wiring of the wiring kit. You will need to check to make sure it's making a solid connection to the correct circuits.

expert reply by: Jameson C