How to Work Lights on a Trailer

The importance of trailer lights that work properly is critical to road safety. Your lights inform other drivers of your intentions to stop and turn, and make the trailer visible, especially at night. Poorly functioning trailer lights can cause an accident, injury and possibly death on the highway, so learn to work and maintain your trailer lights.

Difficulty: Moderately Easy

Instructions

1. Put the trailer plug into the wiring harness on the pulling vehicle and turn on headlights and hazard lights. Check to see if the trailer lights work.

2. Have one person in the vehicle and another checking the brake lights, hazard lights, both turn indicators and backup lights. Back the trailer into a garage or an area that allows you to see the lights' reflection if no one can assist the light check.

3. Find the source of trailer light problems. If one light doesn't work, take the cover off the light, check the connection and change the bulb if necessary.
   

4. Investigate farther if this does not repair your light problem. Change the entire light unit; consider switching to brighter, longer lasting LEDs.
   

5. Work on the trailer lights if none of them light. Check the power connection between the vehicle and the trailer first, and then work toward the back of the trailer.

6. Make sure the ground wire has no problem and all of the wiring is in good repair. Clean rust off the ball connecting the trailer to the truck, because this could cause a poor electrical connection.

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on 5/9/2009 If your trailer lights flicker (while driving or jumping on the trailer), chances are that the ground is bad. Clean any debris off of the trailer ball. If that fails, trace the white wire coming from the connector and ensure that it is attached to the metal of the trailer.