Test G: The Trailer Brakes Are Always Engaged

PINPOINT TEST G: THE TRAILER BRAKES ARE ALWAYS ENGAGED

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 TBC 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 43 (DB).

Possible Causes
^ Fuse(s)
^ Circuit open
^ Circuit shorted
^ Corrosion
^ Pushed-out pins
^ Trailer circuitry
^ TBC module

G1-G2:

G2-G3: