Brake Controller Installed in 2003 Ford Explorer Sport Trac is Melting Brake Stoplight Switch Wire
Question:
I have a 2003 Ford Explorer Sport Trac, no factory brake controller plug. I had a local garage install a wiring harness and 7 terminal socket. Trailer lights work fine without the controller plugged in. However, when plugging in the Agility unit, it was melting the brake switch wire on the truck. Testing found that it the red brake switch wire coming out of the controller is putting out 12v. I assume this is an input wire from the truck brake switch and shouldnt carry a 12v output. White ground and black power wires are not switched. Thanks, Mike.
asked by: Mike M
Expert Reply:
Most modern brake controllers should not output any current on that red wire that attaches to the brake stoplight switch. There are a few of the older time-delayed controllers that would feed back some voltage so that the vehicle brake lamps would illuminate when the override switch was activated.
Since your controller is melting the stoplight switch wire, two possibilities come to mind. Either something is wrong with the interior circuitry of the controller, and it must be replaced, or the controller has been incorrectly installed.
I would recommend reviewing the install procedure, making sure that the correct brake stoplight circuit has been tapped into. If you see a light green, and a red and green striped wire coming off of the switch, the red wire from the controller should be tapped into the light green wire. Using the wrong wire can damage the controller and would certainly cause the melting wire problem you are experiencing.
To review the install instructions, click on the provided link.
