Troubleshooting Trailer Wiring That Activates Both Turn Signals

Question:

Every thing works fine except when you use right turn signal - lights blink bright on trailer and van but the left side blinks less bright on both van and trailer HELP

asked by: Dusty

Expert Reply:

It sounds like the lights on the left side of your van and trailer are activating dimly when you turn on the right hand signal. When this happens the most common cause is bad ground connection. A weak ground can cause all sorts of weird behavior from lights so this is the first and easiest thing to check.

Find the van's wiring harness ground wire; this is usually a white wire with a ring terminal that is attached to the vehicle frame. Remove the ground wire and use some fine (500 grit) sandpaper to clean off that grounding point so that you have a clean shiny bare metal surface. Then reconnect the ground wire terminal. I also recommend applying dielectric grease # 11755 to help protect that connection from future corrosion. If the problem persists then repeat this same process on the trailer's ground wire. You can also refer to the linked article on troubleshooting.

Also make sure that the ground contact on both the vehicle and trailer connectors is clean and free of corrosion.

expert reply by: Adam R