Troubleshooting Some Trailer Marker Lights Not Working While Others Work

Updated 04/17/2023 | Published 04/15/2023

Question:

Wanted to know my side marker lights on the left and back left tail and brake light is but my left side marker lights and right brake lights is not coming on so how can get right side marker light to work

asked by: Glen H

Expert Reply:

With you only having individual lights not working you will need to test the wiring and light bulbs at the lights themselves. You could have a damaged connection if the wiring off the main wiring which would be the reason only certain lights are working. You will need a Test Light # PTW2993 to check the wires going into the lamp are getting the power they need. You can also use it as a jumper to confirm the ground wire has a good connection. By connecting to the ground at the light you may not get the light on the test light but it may cause the marker light to light up if you have a bad ground.

expert reply by: Bud M