Troubleshooting Trailer Wiring Where All Lights are On All the Time

Question:

Boat trailer: everything was working fine, but now all marker and tail lights are on, but no turn signal trailer lights wont blink and no brake lights I **think** the brake lights are on all the time, but could be marker lights. Ive replaced the trailer side plug and the 5 - 7 pin adapter. The truck is new and all lights are working. I believe the reverse solenoid on the trailer may not be working. Could this be causing the problem?

asked by: Mike

Expert Reply:

Typically when this problem happens the issue is that the trailer wiring harness on the tow vehicle is shorted out and is sending power on all circuits at all times. On a newer truck I would not anticipate that being the case though and instead I would look at the wiring of the trailer. Most likely there is a short between the 12 volt accessory circuit and the running light or both stop/turn circuits.

expert reply by: Jameson C