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Test C: The Speed Control Does Not Disengage When the Brakes Are Applied

PINPOINT TEST C: THE SPEED CONTROL DOES NOT DISENGAGE WHEN THE BRAKES ARE APPLIED


C1:






C2-C4:






Normal Operation
The speed control actuator sends a voltage reference signal through circuit CCB15 (BN/GN). The stoplamps provide a ground path that enables speed control operation. When the brake pedal is applied, the voltage goes high and speed control goes into stand-by mode.

Voltage for the speed control servo clutch (internal to the speed control actuator) is supplied by the smart junction box (SJB) to the speed control deactivator switch through circuit CBP26 (BU/WH). The speed control deactivator switch (closed when the brake pedal is not applied) then routes the voltage to circuit CES09 (VT/OG) to the speed control actuator. When the brake pedal is firmly applied, the speed control deactivator switch opens and voltage is no longer supplied to the speed control servo clutch.

Possible Causes
- Circuit CCB15 (BN/GN) open
- Circuit CES09 (VT/OG) short to voltage
- Obstructions to the accelerator pedal or linkage
- Speed control deactivator switch
- Stoplamp switch
- Speed control cable
- Accelerator cable
- Speed control actuator