Running Lights Are Dim, But Why?

Published 08/17/2018

Question:

running lights are so dim you cant see them during the day light hours but our on. can see at night. brake, turn single work fine. tester indicates 12v power. using wiring harness on car that came with hitch.

asked by: Lynn R

Helpful Expert Reply:

In many cases a bad ground is to blame for this type of issue so you are going to want to start by taking a look at are the ground connections. Make sure your grounds are securely attached to bare metal surfaces free of any paint, dirt or corrosion of any kind. Also check your wiring thoroughly to ensure there are none that are crimped, broken or otherwise damaged.

It is also possible you have too many running lights and that is causing an overload on the system, particularly if you are using incandescent lights. You can try removing the bulbs from some of your running lights to see if that fixes the issue.

I've added links to a pair of help articles on trailer wiring that you may also find useful, and a video of the circuit tester # PTW2993 in action.

expert reply by: Kyle S