Troubleshooting Trailer Running Lights Staying on with Wiring Kit Installed on 2013 Scion tC

Question:

2013 scion tc. Trailer running lights stay on all the time. Checked ground cleaned the connection, it was not corroded. Still lights stay on.

asked by: Scott

Expert Reply:

The trailer wiring harness for your 2013 Scion tC is the Hopkins # HM11141964. This uses a converter box that pulls in power directly from your battery via the lead wire and then use the other wires as "triggers" to tell the box when to send power to the correct functions.

If the 4-Way connector and the ground look clean then you'll want to test the wires going into and out of the converter box. What I'm guessing is happening is that power is jumping from that lead to the running light circuit somewhere along the line (maybe even in the box) so if the running light wire doesn't have power going into the box but it does when it's coming out then that means you need a new wiring kit.

Attached are some review videos and a helpful article about troubleshooting trailer wiring. If you're still having issues please reach out and I can help you troubleshoot further.

expert reply by: Jon G