Left Brake and Turn Signal on Trailer Connector Not Working on 2016 Ford F-150
Question:
Brake and signal lights on my 2016 F150 work fine on truck but no left signal/brake at the trailer tow plug. I’ve replaced the 20A fuse in port 35 in the min fuse box with no success. Any idea what else it could be? Thank you.
asked by: Kalvin
Expert Reply:
It sounds like you've isolated the issue to your 7 way connection on the truck, and the left turn signal/brake light is controlled by the circuit at 9 o'clock when looking at the front of your vehicle's 7 way connection (most likely a yellow or red wire).
I would start with making sure that the ground wire (white) on your 7 way is connected firmly to a rust and paint free spot on the vehicle's frame; it's entirely possible that the ground wire is loose and causing this issue. You'll also want to make sure that the 7 way connector is clean and free from debris/corrosion.
Next, you'll want to turn the left turn signal on and use a circuit tester like the # PTW2993 to check for a signal on the circuit behind the 7 way connection on the vehicle(wire at 9 o'clock when looking at front of plug)- if there is no signal, you'll need to trace the wire back and check for damaged/cut wires along the way. If you do have a signal behind the wire, your 7 way is damaged and it will need to be replaced.
If you've gone through these steps and the issue has not been resolved, let me know and I have a couple of other things you can look at to get this resolved. I've also linked one of our help articles on 7 way wiring that has some diagrams in it of wiring schematics that you may want to refer back to.
Product Page this Question was Asked From
Featured Help Information
Miscellaneous Media
Continue Researching
- Shop: 7-Way to 4-Way/5-Way Trailer Adapter for Vehicles with Lamp-Out Sensors Towing Trailers with LEDs
- Shop: Provider ST205/75R15 Radial Trailer Tire with 15" White Spoke Wheel - 5 on 5 - Load Range D
- Shop: Adco SFS AquaShed RV Cover for Travel Trailers up to 18' Long - Gray
- Shop: Adco Olefin HD RV Cover for Travel Trailers up to 18' - All Climate + Wind - Gray
- Shop: Extang Trifecta 2.0 Soft Tonneau Cover - Folding - Vinyl
- Shop: Tonneau Cover
- Shop: RV Camera
- Shop: RV Exterior Lighting
- Shop: RV Covers
- Video: Adco Travel Trailer SFS AquaShed Cover Review
- Q&A: Left Turn Signal is Faint on Trailer
- Shop: Trailer Wiring
- Shop: 7-Way Trailer Adapter for Towing Trailers with LED Lights
- Q&A: Troubleshooting Lack of 12V Power at 7-Way Trailer Connector on 2019 Ford F-150
- Q&A: Troubleshooting No Right Stop/Turn Lights on P.J. Trailer
- Q&A: Solution for Powering Brake Controller Install of 2019 Ford F150 with Factory Tow Package
- Shop: Hook Probe Circuit Tester
- Shop: Trailer Hitch
- Search Results: 44649
- Article: Trailer Wiring Diagrams
- Q&A: Hub And Drum Replacement for 90865 Rockwell Hub and Drum
- Video: Choosing the Right Trailer Wiring
- Q&A: Trailer Grease Seal to Replace 127194TB
- Search Results: 68149
- Video: EcoHitch Hidden Front Mount Trailer Hitch Installation - 2021 Ford F-250 Super Duty
- Article: Brake Controller 7- and 4-Way Installation Kit (ETBC7)
- Video: Thule Carbon Bike Frame Protector Review
- Article: How to Choose the Right Trailer Hitch Class
- Search Results: 25580
- Shop: Suspension Enhancement
on Wiring
