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Brakes With Factory Brake Controller Does Not Engage


I have a rv in which the brakes does not engage. When the brakes are applied in the truck I can hear a slight buz sound but will not engage. I removed the hub and found when the brakes are applied the magnet does not become magnetic. My GMC has a factory installed brake switch which I adjusted to 10. I was looking at your never adjust brake set up but not sure if replacing all four wheels will solve my problem.


Expert Reply:

When you hear the buzzing sound when the brakes are applied, that sound is power going back to the brakes, or at least part of the way, lets get this issue corrected. Since you have a factory brake controller, first we need to make sure that both the 7-Way on your tow vehicle and your trailer are fully functioning. Start off by looking for any corrosion build-up that could be causing the issue on both 7-ways and clean it.

Next, test the functions of the 7-Way on your tow vehicle you can use a Circuit Tester # 40376 and test each pin as you have a helper inside the vehicle go through the functions. To test the brakes you will want to set the brake controller to the highest setting and send power to the 7-Way by using the manual override. This should send 12V power to the pin on the 7-Way that activates the trailer brakes. On the tow vehicle end this should be the pin in the 5 O'clock position.

If the 7-Way connector on your 7-Way doesn't get 12V power when the manual override is used then you will want to sever the brake controller wire, that goes to the 7-Way, about 6 inches away from the brake controller itself. If that wire is still not getting power when the manual override is used (and you brake controller is wired correctly) then you will need to replace your brake controller.

To test the brakes on your trailer you will want to use a 12V power source, like the battery on your tow vehicle, and test the pins on your trailer side 7-Way. You will want to especially pay attention to the pin in the 7 O'clock position (which is opposite of your tow vehicle) since that is the pin that should be activating the brakes. When you apply the 12V of power your brakes should activate and you will hear a quiet humming.

If the 7-Way on your tow vehicle is working correctly but when you apply the 12V power to the pin for the brakes on your trailer and it isn't working then you will want to check the wiring on your trailer. Look for any places where the wiring might be exposed, corroded, bent, or damaged and replace it. For the brake wiring you will want to use 10 Gauge Wire # 10-1-1 and Butt Connectors # DW05745-5.

Testing the brakes would be the next step. There are 4 different tests that can be done to check the brake magnets on your trailer. The first test you should do is to use a multimeter # PT89ZR to check the amperage of your trailer braking system. The trailer brake magnets will draw amperage from the brake controller based on the output voltage sent by the brake controller. Performing this test will let you know if the magnets are functioning properly or if further testing is required. If you are getting full power, then the magnets are either bad or the brakes need to be adjusted. If the brakes are not engaging at all they may need to be replaced. I have an help article that goes into detail on how to test Trailer Brake Magnets.

The benefit of the Dexter Nev-R-Adjust Electric Trailer Brake Assembly # 23-465 reduces or virtually eliminates the need to ever have your brake shoes adjusted periodically. It also optimizes your pad life. Our customer buy products like the Nev-R-Adjust brakes to eliminate or reduce the maintenance on the brake assembly itself.

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