ANOTHER Trailer Brake problem

Discussion in 'Trucks and Trailers' started by WLC, May 26, 2005.

  1. WLC

    WLC LawnSite Member
    from NE TN
    Posts: 80

    2001 F150... I bought the harnesses (2) to connect my aftermarket brake controller and 7 pin connector into the trucks factory plugs/wiring. My trailer brakes work only if I manually operate the controller switch with my hand while driving. In my previous truck I had this same controller which was activated each time the trucks brake pedal was depressed. What am I missing? All brake lights and signals perform fine.
     
  2. greywynd

    greywynd LawnSite Member
    Posts: 132

    Hopefully you have a test light or voltmeter....test and see if you have power going to the input lead of the controller when you apply the brake pedal. If you do, check the output lead as well, if there's power there, there's a problem somewhere between there and the trailer connector. If there's nothing on the input, then there's a problem in the truck somewhere. If there's input, and nothing on the output, make sure that all the controls on the brake controller are set to high/max, and try again. If there's still nothing, I would suspect the controller itself.

    Edit: After reading your post again, I realized that your trailer brakes are working, only when you apply them manually. I would check the input side of your controller...I would suspect it's not getting a signal that your brakes are on. On my controllers, there's an LED that comes on when the pedal is depressed, whether I have a trailer connected or not.
     
  3. WLC

    WLC LawnSite Member
    from NE TN
    Posts: 80

    Thanks Grey!....... Exactly! my controller has the LED also....only illuminates when I operate the controller manually, I can feel the brakes on the trailer at that time too. When I apply the trucks brake pedal....No light & No brakes..... I was trouble shooting the trailer/ truck connection...... then began to realize that the problem may lie in between the trucks OEM connection and the controller.........since the trailer brakes work when actuated manually. I bought the aftermarket adapter to plug into the OEM connection on the truck and assumed all's well in that area???? Perhaps you can bring me up to speed as to what the "SYNC" slide switch on the controller does again? I couldn't tell you where the literature on my controller is..... middle of the season and transferring trucks!!!!! :dizzy:

    Thanks again!
     
  4. greywynd

    greywynd LawnSite Member
    Posts: 132

    So, you have power to the controller, you have brakes, you just don't have a signal coming in. Going from my poor memory, there should be 4 wires going into the controller, blue (Brake out) , white (ground?) black (12v pos?) and red(I think, should be on when brake pedal is pressed)

    Use a test light to make sure your controller is getting power. Also, double check to make sure your brake lights on the truck are working.....depending on the wiring, if you blow the fuse for brake lights, you may also lose the signal for the controller. With the antilocks on the trucks, you may or may not be able to hook into the brake light wire for a signal, I don't have any literature for my controllers accessible right now either.

    The 'snyc' control is kind of a sensitivity, or reaction adjustment. If you set it on the high side, for example, it will cause the trailer controller to activate the brakes without a lot of pressure on the actual brake pedal. I tend to run mine slightly that way so that the trailer will 'drag' the truck ever so slightly when braking, and the output around half. This way if for some reason I need a little more, I can lock up the trailer by manually activating the electric brake override. I would think that you should have something regardless of the setting on this, but if it's to minimum, maybe not....you could try it at max and see if the LED lights at all if you step on the pedal.

    I would have to think that the controller isn't getting the signal that the brake pedal is depressed, either a poor connection or not connected to the right spot. If I get a chance tomorrow, I'll try to see if I can find one of the manuals for mine to see where to hook up on your truck.
     

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