2010 Ford F-150 Brake Controller Says No Trailer Connected with a Trailer Connected
Question:
have no trailer brakes all wires seem intact 2010 f150 says no trailer attached brake lights work turn lights work marker work just no brakes gain is at 10
asked by: Mike
Expert Reply:
When a brake controller says that there is no trailer attached even if there is a trailer attached that means that it is not sensing the brake magnets. This could be because of a problem on the brake output wire such as a severed wire. It could also mean there is dirt or corrosion on/inside the vehicle or trailer side connectors.
There are some tests you can do to determine where the problem is. In the truck cab you will need to sever the brake output wire several inches from the back of the controller. Then use a circuit tester such as # PTW2992 to test the end of the blue wire coming out of the controller. It should only have power when you apply the manual override (or brake pedal on some controllers). If it shows power at idle, then there is something wrong with the controller and it will need to be replaced.
If it tests fine then reconnect the blue wire. Then move on to the truck side trailer connector. Many times, dirt or corrosion can cause a short in a trailer connector. Make sure the truck and the trailer side connectors are clean and free of corrosion inside and out.
You can test the brake output pin and it should only show power with the manual override. If it shows power any other time then there is a short somewhere between the connector and the brake controller you will need to track down.
If the truck side checks out fine then it could be the wiring to the brake magnets or the magnets themselves. Inspect the power wires to the magnets and look for pinched, frayed, or damaged wires and fix as needed. Make sure the ground wires are attached to clean and corrosion free bare metal surfaces.
You can visually inspect the magnets and if you can see the copper windings coming through the magnets will need to be replaced. To further test the magnets you can follow the help article I have linked. I have also included some help articles on testing and troubleshooting brake controllers for you.
Products Referenced in This Question
Product Page this Question was Asked From
Continue Researching
- Video: Curt T-Connector Vehicle Wiring Harness Installation - 2019 Ford F-150
- Shop: Curt T-Connector Vehicle Wiring Harness with 7-Way Trailer Connector
- Shop: Universal Installation Kit for Trailer Brake Controller - 7-Way RV and 4-Way Flat - 10 Gauge Wires
- Shop: Trailer Wiring
- Article: Brake Controller 7- and 4-Way Installation Kit (ETBC7)
- Q&A: How to Tell If MORryde Rubber Equalizers Will Fit Trailer
- Article: Trailer Wiring Diagrams
- Q&A: Correct Replacement for AL-KO 7230 Hub/Drum and Brakes
- Article: Trailer Maintenance Schedule
- Article: How to Install E-Track in 3 Easy Steps
- Q&A: Replacement for Demco Master Cylinder 05680-C for Drum Brakes
- Article: 7 Common Questions Everyone Has About Trailer Tires
- Q&A: Replacement Kwikee Electric Steps for a 2005 Jayco Greyhawk 31SS
- Q&A: When to Replace Dexter Nev-R-Lube Bearings
- Article: Must Have RV Accessories that Will Make or Break Your Trip
- Q&A: How to Determine Correct Rise or Drop for Blue Ox SwayPro Weight Distribution System
- Q&A: Recommended Square Bulldog Jack with 5,000 lb Capacity
- Article: How to Charge a Dump Trailer Battery