Brake Controller Says No Trailer Connected with Trailer Connected to 2010 Ford F-250
Published 09/17/2014
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Question:
It tells me trailer not connected but the tail lights, brake lights etc. work on the trailer when connected why wouldnt the brakes be connecting and or why does it tell me no trailer connected and wont let me set the strength of the brake?
asked by: Kathy
Expert Reply:
The trailer lights and the trailer brakes are on separate circuits, and one does not affect the other so there is some other reason why the brake controller on your 2010 Ford F-250 is not sensing the trailer.
If it is a factory brake controller, we do not have a lot of experience with those, but it could be a dirty or corroded trailer connector on either the truck side 7-Way or the trailer side 7-Way. This is also a potential problem for aftermarket brake controllers.
There are some things you can test to determine where the problem is. Please note the following is for an aftermarket controller. Testing procedures for the factory controller should be verified with a Ford technician.
In the truck cab you will need to sever the blue 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 certain 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 like I mentioned earlier.
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.
Product Page this Question was Asked From
Dexter Electric Trailer Brake Assembly - 12" - Left Hand - 6,000 lbs
- Accessories and Parts
- Trailer Brakes
- Electric Drum Brakes
- LH
- 6000 lbs
- Brake Assembly
- Manual Adjust
- 12 x 2 Inch Drum
- Dexter
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