Troubleshooting Test Light Pulsating When Plugged Into Vehicle Side Connector On Truck

Updated 02/09/2021 | Published 02/05/2021

Question:

I have to push reallyinch hard on brake pedal to get test light at rear of truck at trailer connection. When I do test light pulsates. Is it suppose to do that? I figure the problem at brake pedal is brake light is not adjusted properly. But still questions in my mind.

asked by: Richard K

Helpful Expert Reply:

It sounds like you are not getting a good connection when you are applying the brakes on your truck which is causing the pulsating light on the test light.

You should not have to press hard on your brake pedal for the tail light or trailer brake functions to work properly.

I recommend checking the red wire from your trailer brake controller to the cold side of your brake pedal switch that only gets power when the brakes are activated, and make sure the connection is secure. If you are still getting a intermittent connection double check that the ground for the trailer brake controller is connected to clean, corrosion free metal.

It also would be a good idea to check the inside of your 7-way connector for corrosion or debris that could be causing a poor connection.

I included a link to a helpful article on wiring for you to take a look at.

expert reply by: Samuel C