Troubleshooting Running Lights Flicker When Braking and Hitting Bumps
Updated 12/15/2025 | Published 11/06/2024
Question:
My trailer lights work except the running lights they flicker when I go over a pump and they flicker when I tap the brake, but I can’t get the running lights to stay on. I’ll check the wiring from the pins to the back of the trailer and cannot find any brakes in the line or backgrounds. No fuses are blown. Any ideas?
asked by: Christopher D
Expert Reply:
Hi Christopher; have you checked your ground connections? That may have been auto correct when you said "backgrounds" but it could be a loose ground and the braking/bumps are enough that it is moving it around causing the running lights to flicker. Since you can't find anything else in the trailer wiring I would look at the vehicle. You can check out your vehicle connector and inspect the wiring but it will be really hard to use a tester to see if the vehicle is the issue since it requires moving the vehicle.
If possible, I would hook it up to another trailer and see if you experience the same issues. You could also try towing your trailer with a different tow vehicle if you can borrow one from friends or family. That would help you narrow down the issue between the tow vehicle and trailer.
Product Page this Question was Asked From
Pollak Metal 7-Pole, RV-Style Trailer Socket - Vehicle End
- Custom Fit Vehicle Wiring
- Trailer Hitch Wiring
- Vehicle End Connector
- 7 Blade
- Plug Only
- Pollak
more information >
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Robin H.
12/15/2025
Hey Christopher, did trying another trailer or tow vehicle help you figure out if the flickering lights came from the trailer or the vehicle side? Knowing what you found could help others track down similar wiring issues.