Troubleshooting Low Taillight Circuit on Trailer Taillight Converter

Updated 03/12/2015 | Published 03/11/2015

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Question:

Brake and turn signal work fine and are nice and bright. Ground is good. I checked voltage at the vehicle flat 4 connector coming off the T- Connector kit and only have 3.5 volts at the brown wire. I new the fuse was good since brake and turn signal are ok but verified anyway. Does this look like a converter issue? Thanks.

asked by: John F

Expert Reply:

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