Solution for Trailer Wiring for 2018 Mazda CX-5 that Has Voltage all the Time

Published 07/28/2026

Question:

2018 cx 5, I have a curt t connector. At the plug connector for the trailer I have constant power to the green wire all the time. With the car off, the passenger tail light stays on all the time. The connection box gets very hot. Would you send me a wire diagram for the box hookup from the car & from the box to the trailer lights ? Thank you Mark

asked by: Mark K

Expert Reply:

Hey Mark, what has happened is the converter box has shorted out and only solution is to be replace the entire kit. So for your 2018 Mazda CX-5 you would need the Curt kit part # C56377 as a replacement. When a trailer wiring harness encounters a trailer wiring short it is common for them to short out and have this happen. What kind of trailer do you have?

expert reply by: Jameson C