Neither Brake Controller nor Break Away Kit Can Stop Trailer
Updated 03/11/2014 | Published 03/10/2014
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Question:
Hello, Thanks in advance for your help. I have a Ford F150 with the tow package pulling a 24foot RV with duel axles and 10inch Dexter brakes on all four wheels. Not sure what brand the controller is, very basic with a red led light, a slider override and a adjustment wheel on the side. I have the adjustment turned to max. When I drove this for the first time it felt like the trailer wasnt slowing down enough when I push on the truck brake pedal. If I use the controller override I was able to almost lock up the trailer brakes. Since then I pulled all the wheels, adjusted all the brakes, and when I had the wife push the brake pedal all the magnets would just barely hold a large screwdriver. But when I had her push the override on the controller there was a definite increase in the magnet. This was the case on all four brakes. I have not drove it since adjusting the brakes. Is this normal? Is it possible the controller is bad? I looked under the dash and the controller is spliced into a unplugged male plug. I also have tested the break away brakes, I do have a new fully charged battery installed. When I pull the plunger out I can still roll the trailer until I tap the brake pedal in the truck, or slide the override, then the trailer brakes lock up. I do get battery voltage on both sides of the break away plunger contacts when plunger is out. Again I have not tried driving it since cleaning and adjusting brakes. Thanks again for your help!
asked by: Marcus
Expert Reply:
The manual override on a brake controller is going to apply the full amount of power to the brakes up to the level it is set at. If at the max setting that is how much power it will send back. The brake pedal will either work in much the same way or it will gradually ramp up the power. Either way when set to the max it should eventually send full power back.
Some proportional brake controllers will not send power back unless the vehicle is moving. I do not think this is the issue though since you experienced the problem also while driving.
It sounds like there is either a connection problem on the red wire or there is something wrong inside the brake controller and it needs to be replaced. Check the connection of the brake controller red wire and make sure that everything is secure. If it is then to further test the controller you will need to sever the blue wire several inches from the back of the controller.
Then with the controller set to the max use a multimeter such as # PT89ZR to test for voltage at the blue wire coming out of the controller. Test it both with the brake pedal and with the manual override, one at a time. They should both be at least 12 volts. If the brake pedal does not provide the proper voltage then there is some issue inside the controller and it will need to be replaced.
If it shows no voltage at all with the brake pedal then that normally indicates a blown stop light or CHMSL fuse. I have included a couple of help articles on troubleshooting brake controllers for you.
The break away is another issue. It should be able to lock the brakes once the pin is pulled. If it is not doing so then there is either a wiring problem or something is wrong with the battery. Make sure that the wiring is not frayed and that the grounds are attached to clean and corrosion free bare metal surfaces. I included some links on break away kits for you as well.
The issue might also be related to the brake magnets. Check the brake magnet wiring (power and ground wires) and make sure they are not frayed and that the power wire is unobstructed and not pinched or sandwiched anywhere. And make sure the grounds are attached to clean surfaces near the magnets. You can test the magnets by following the help article I have linked. First visually inspect the magnets and if you can see the copper windings coming through then the magnets will need to be replaced.
