Pinpoint Test B : The Trailer Brakes Are Always Engaged: Notes
WARNING: This page is about a different car, the 2017 Lincoln Navigator and 2017 Ford Expedition. However, it is still accessible from the selected car via links, so may be relevant.
NOTE:
Carry out all pinpoint tests without
a trailer connected to the vehicle.
Refer to Trailer/Camper Adapter , for schematic and connector information.
Normal Operation and Fault Conditions
The braking energy provided to the trailer is modulated with a PWM signal that varies between 0 volts and battery voltage, according to the TBC module gain setting, the higher the duty cycle the more braking power available. With the vehicle stationary and with the manual slider switch fully to the left with a gain of 10, there should be 10-12 volts supplied to pin 3 of the 7-pin trailer tow connector. The TBC module also receives information from the brake pressure switch (also called the speed control deactivation switch) and the stoplamp switch from the PCM over the High Speed Controller Area Network (HS-CAN).
Possible Causes
- Wiring, terminals or connectors
- TBC module
- Trailer