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

Refer to appropriate SYSTEM WIRING DIAGRAMS article, Speed Control for schematic and connector information.

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.

This pinpoint test is intended to diagnose the following:

• Wiring, terminals or connectors
• Obstructions to the accelerator pedal or linkage
• Speed control deactivator switch
• Stoplamp switch
• Speed control cable
• Accelerator cable
• Speed control actuator

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

1. C1 CHECK THE SPEED CONTROL CABLE/ACCELERATOR CABLE 
   • Key in OFF position.
   NOTE: Make sure the floor mat, insulation, wiring harnesses location, and other items do not interfere with the accelerator pedal and linkage.
   • Visually inspect the speed control cable connections, the throttle body linkage, and the speed control actuator pulley cover.
   • Are the speed control cable connections, the throttle body linkage, and the speed control actuator pulley cover OK?  
   1. YES  : Go to  C2.
   2. NO  : INSTALL a new speed control cable or accelerator cable. To INSTALL a new speed control cable, REFER to Speed Control Cable . TEST the system for normal operation. To INSTALL a new accelerator cable, REFER to ACCELERATION CONTROL article. TEST the system for normal operation.
2. C2 CHECK THE STOPLAMPS FOR CORRECT OPERATION 
   • Check the stoplamps for correct operation by firmly applying and releasing the brake pedal.
   • Do the stoplamps operate correctly? 
   1. YES  : Go to  C3.
   2. NO  : REFER to EXTERIOR LIGHTING article to continue diagnosis of the stoplamps.
3. C3 CHECK THE SPEED CONTROL DEACTIVATOR CIRCUIT 
   • Key in ON position.
   Fig 1: Checking Circuit For Voltage
   Courtesy of FORD MOTOR CO.
   • Measure the voltage between the speed control actuator C122-9, circuit CES09 (VT/OG), harness side and ground while firmly applying the brake pedal.
   • Is any voltage present? 
   1. YES  : Go to  C4.
   2. NO  : INSTALL a new speed control actuator. REFER to Speed Control Actuator . TEST the system for normal operation.
4. C4 CHECK CIRCUIT CES09 (VT/OG) FOR A SHORT TO VOLTAGE 
   • Key in OFF position.
   • Disconnect: Speed Control Deactivator Switch C277
   • Key in ON position.
   Fig 2: Checking Circuit For Voltage
   Courtesy of FORD MOTOR CO.
   • Measure the voltage between the speed control actuator C122-9, circuit CES09 (VT/OG), harness side and ground.
   • Is any voltage present? 
   1. YES  : REPAIR the circuit. TEST the system for normal operation.
   2. NO  : INSTALL a new speed control deactivator switch. REFER to Speed Control Deactivator Switch . TEST the system for normal operation.