Troubleshooting Trailer Wiring Harness Converter Box

Updated 06/25/2018 | Published 06/22/2018

Question:

1. I have a 2009 Hyundai Tuscon. I have checked all the lights on the vehicle and they all work fine. 2. I went to plug in my trailer the other day and nothing came on. The trailer worked fine a year ago. 3. I checked the trailer over and found nothing unusual. 4. On the vehicle I checked the plug with a led test plug. Everything seemed to be good. All the led lights on the tester were on. But when I plug into trailer nothing. 5. When I tested the vehicle plug with a old style test light tester, the turn signals worked but if I turned on the head lights, the turn signal would blink along with the running lights. Can the converter box be bad?

asked by: Bill K

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 # 3808 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.

expert reply by: Jameson C