Troubleshooting Trailer Tail Lights Not Working When Brake/Turn Lights Work
Question:
HAVE SIGNAL BRAKE FLASHERS BUT NO TAIL LIGHTS HAVE NO POWER AT THE PLUG CANT FIND A BLOWN FUSE HELP
asked by: KIRBY G
Expert Reply:
Since you have brake and turn but not taillights, the issue can be a fuse, a relay, bad wiring, or a weak connection. I recommend you first start with the wiring connection by cleaning it up with some sandpaper or steel wool, and then testing the pin for power.
If you don't have power, I recommend first checking your ground connection at the trailer plug. A weak ground connection can cause some functions to work and others not to work. Next, I recommend checking your owner's manual for a fuse or relay location that has to do with trailer taillights/running lights. If there is nothing in the fuse or relay information for trailers, then I recommend tracing your wiring from that pin location back using a circuit tester like # PTW2993 probing the wire every few feet. When you find the short, replace the wire with # 16-1-1 sold by the foot and butt connectors # DW05744-5.
If you tract to a converter box or module and you test signals coming in but not coming out, then the module will need replaced.
Products Referenced in This Question
Deka Heat Shrink Butt Connector - 16-14 Gauge - Nylon Insulation - Blue - Qty 5
- Wiring
- Wire Connectors
- Butt Connectors
- 16-14 Gauge
- Deka
more information >
Product Page this Question was Asked From
Continue Researching
- Article: Trailer Wiring Diagrams
- Q&A: All Parts Needed to Flat Tow 2014 Chevy Silverado 1500 Behind Motorhome
- Q&A: Trailer Running Lights Do Not Work but Brake Lights and Turn Signals Do Work
- Article: Wiring Trailer Lights with a 7-Way Plug (It's Easier Than You Think)
- Article: Brake Controller 7- and 4-Way Installation Kit (ETBC7)
- Article: Brake Controller Installation: Starting from Scratch
- Article: Testing Trailer Brake Magnets for Proper Function
- Article: Troubleshooting 4 and 5-Way Wiring Installations
- Article: Troubleshooting Brake Controller Installations
- Q&A: How to Make an Adapter to Go from Semi Truck 7-Way Round to RV Style 7-Way Blade on Trailer
- Q&A: How to Test Brake Controller without Trailer Connected
- Q&A: Trailer Lights Left Side Turn Signal and Brake Lights Not Working
- Q&A: Troubleshooting No Running Lights on Trailer but Turn Signals and Brake Lights Work
- Q&A: Recommended Flat Towing Parts for a 2024 GMC Canyon Denali