Troubleshooting T-One Wiring Low Power on a 2018 Honda Civic

Updated 03/13/2023 | Published 03/11/2023

Question:

Troubleshooting assistance with 2018 honda civic trailer wiring. Lights arent working. Voltages may be off on output to trailer but need what theyre supposed to be to be sure

asked by: Mike

Expert Reply:

You should be seeing 12V with different amps when testing the 4-Way T-One Vehicle Wiring Harness # 118686 on your 2018 Honda Civic. When it comes to amps we're looking for 7.5 amps for the tail lights and then 5 amps for the stop/turn circuits.

What we usually find to be the problem with wiring is a bad ground. Check to make sure the ground is secured to a clean, bare-metal surface and that all of the other connections are in good order.

If the power going into the black box is significantly different than the power coming out then that could also mean a bad module and you'll want to take advantage of the 1-year limited warranty if that still applies to you.

Attached is a troubleshooting help article for you to check out.

expert reply by: Jon G