F 250 2WD Super Duty V8-5.4L (2008)
E7 (Continued)-E8
Test F: The Trailer Brakes Are Always Engaged
Pinpoint Test F: The Trailer Brakes are Always Engaged
NOTE: Carry out all pinpoint tests without a trailer connected to the vehicle.
Refer to Vehicle/Diagrams, Trailer/Camper Adapter for schematic and connector information.
Normal Operation
The braking energy that is provided to the trailer is varied with a pulse width modulated (PWM) signal that switches between 0 volt and battery voltage,
according to the trailer brake control (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 greater than 10-12 volts supplied to trailer tow C4099-3 circuit
CAT19 (BU).
This pinpoint test is intended to diagnose the following:
^
Fuse(s)
^
Wiring, terminals or connectors
^
TBC module