Troubleshooting Trailer Turn and Brake Lights Not Working as They Should
Trailer brake and turn lights not working on the left side ... but when headlight is on, it works not blinking just solid. Any ideas? Please advise. Thank You
asked by: PJ P
I do have ideas about the issue and it sounds like you do not have a good ground, which is what causes the majority of trailer light problems. What you need to do is make sure your grounds are attached to bare metal surfaces and free of any paint, dirt or corrosion.
Another thing to take a look at is both your vehicle and trailer connectors; check them for corrosion which can be green or white in color. A build-up of corrosion can interfere with the signals getting through the connectors so if it is present you will need to either replace the plug or clean the corrosion.
Finally, check your wiring thoroughly to ensure there are none that are crimped, broken or otherwise damaged. I have added links to a pair of help articles on trailer wiring, including a troubleshooting guide which I highly recommend taking a look at.
- Q&A: Trailer Brakes Lock Up When Connected to Truck
- Q&A: Testing for Proper Voltage on the Brake Output Circuit
- Article: Trailer Wiring Diagrams
- Article: Wiring Trailer Lights with a 7-Way Plug (It's Easier Than You Think)
- Article: Testing Trailer Brake Magnets for Proper Function
- Q&A: Trailer Lights Work But Brakes are Not Working
- Q&A: How Long Does It Take to Install B&W Turnoverball Underbed Gooseneck Trailer Hitch BWGNRK1020
- Article: Brake Controller 7- and 4-Way Installation Kit (ETBC7)
- Article: Troubleshooting Brake Controller Installations
- Q&A: How Much Voltage Should Be Applied To Brakes on Trailer w/ Electric Brake Controller
- Q&A: Troubleshooting Voltage Drop to Trailer Brake Assemblies
- Q&A: How to Test Brake Controller without Trailer Connected
- Article: Wiring Trailer Lights with a 4-Way Plug (It's Easier Than You Think)
- Article: How to Install a Brake Controller on Chevrolet / GMC 1999-2006 Pickups