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Test A: Speed Control Inoperative

  1. Turn ignition switch to LOCK position. Disconnect speed control servo/actuator harness connector C177. Speed control servo/actuator is located in right front side of engine compartment, behind power steering fluid reservoir. See Figure. Turn ignition switch to ON position. Using a voltmeter, measure voltage between speed control servo/actuator harness connector C177 terminals No. 7 (Yellow wire) and No. 10 (Blue wire). See Fig 1. If voltage is 10 volts or less, go to next step. If voltage is more than 10 volts, go to step  4.
  2. Turn ignition switch to LOCK position. Inspect Central Junction Box (CJB) ASC fuse (10-amp). CJB is located under left side of instrument panel. Fuses are identified on CJB cover. If fuse is okay, go to next step. If fuse is blown, replace fuse and retest system operation. If fuse blows again, check for short to ground in Yellow wire between air bag sliding contact, CJB and speed control servo/actuator. See WIRING DIAGRAMS . Replace fuse and retest system operation.
  3. Ensure ignition switch is in LOCK position. Measure resistance between ground and speed control servo/actuator harness connector C177 terminal No. 10 (Blue wire). If resistance is less than 5 ohms, repair open in Yellow wire between CJB and speed control servo/actuator. See WIRING DIAGRAMS . Retest system operation. If resistance is 5 ohms or more, repair open in Blue wire between ground and speed control servo/actuator. See WIRING DIAGRAMS . Retest system operation.
  4. Check stoplight operation by pressing and releasing brake pedal. If stoplights operate properly, go to next step. If stoplights do not operate properly, repair stoplights as necessary. See EXTERIOR LIGHTS in appropriate SYSTEM WIRING DIAGRAMS article in ELECTRICAL.
  5. Ensure ignition switch is in LOCK position. Measure resistance between speed control servo/actuator harness connector C177 terminals No. 4 (Green wire) and No. 10 (Blue wire). If resistance is 20 ohms or more and vehicle is equipped with M/T, go to next step. If resistance is 20 ohms or more and vehicle is equipped with A/T, repair open in Green wire between Brake Pedal Position (BPP) switch and speed control servo/actuator. See WIRING DIAGRAMS . Retest system operation. If resistance is less than 20 ohms, go to step  8.
  6. Disconnect Clutch Pedal Position (CPP) switch harness connector C292. CPP is located on top of clutch pedal support. Measure resistance between CPP switch terminals (component side). See Fig 2. If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, replace CPP switch and retest system operation. See CLUTCH PEDAL POSITION SWITCH  under REMOVAL & INSTALLATION.
  7. Turn ignition switch to OFF position. Disconnect Brake Pedal Position (BPP) switch harness connector C245. BPP switch is located on top of brake pedal support. Measure resistance of Green wire between BPP switch harness connector C245 and CPP switch harness connector C292 terminal No. 3. See Fig 3. If resistance is less than 5 ohms, repair open in White or Green wire between CPP switch and speed control servo/actuator. See WIRING DIAGRAMS . Retest system operation. If resistance is 5 ohms or more, repair open in Green wire between CPP switch and BPP switch. See WIRING DIAGRAMS . Retest system operation.
  8. Measure voltage between speed control servo/actuator harness connector C177 terminals No. 9 (Green/Yellow wire) and No. 10 (Blue wire). If voltage is 10 volts or less, go to next step. If voltage is more than 10 volts, go to step  11.
  9. Deactivate air bag system. See appropriate AIR BAG RESTRAINT SYSTEMS article in RESTRAINTS. Ensure ignition switch is in LOCK position. Disconnect deactivator switch harness connector C208. Deactivator switch is located behind left side of instrument panel. Measure resistance between deactivator switch terminals (component side). See Fig 2. If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, replace deactivator switch and retest system operation. See DEACTIVATOR SWITCH  under REMOVAL & INSTALLATION.
  10. Using a voltmeter, measure voltage between ground and deactivator switch harness connector C208 Green/White wire terminal. If voltage is more than 10 volts, repair Green/Yellow wire between deactivator switch and speed control servo/actuator. See WIRING DIAGRAMS . Retest system operation. If voltage is 10 volts or less, repair Green/White wire between BPP switch and central junction block. See WIRING DIAGRAMS . Retest system operation.
  11. Ensure ignition switch is in LOCK position. Measure voltage between speed control servo/actuator harness connector C177 terminals No. 5 (Red/Yellow wire) and No. 10 (Blue wire). If any voltage is present, go to next step. If no voltage is present, go to step  14.
  12. Disconnect speed control switch harness connector C269. Turn ignition switch to ON position. Measure voltage between speed control servo/actuator harness connector C177 terminals No. 5 (Red/Yellow wire) and No. 10 (Blue wire). If any voltage is present, go to next step. If no voltage is present, replace speed control switches and retest system operation. See SPEED CONTROL SWITCHES  under REMOVAL & INSTALLATION.
    13. NOTE: Air bag sliding contact may also be referred to as air bag clockspring.
  13. Turn ignition switch to LOCK position. Disconnect air bag sliding contact harness connector C248. Air bag sliding contact is located on steering column, under steering wheel. Connector is located under lower steering column shroud. Turn ignition switch to ON position. Measure voltage between speed control servo/actuator harness connector C177 terminals No. 5 (Red/Yellow wire) and No. 10 (Blue wire). If any voltage is present, repair short to voltage in Red/Yellow wire. Retest system operation. If no voltage is present, replace air bag sliding contact and retest system operation. See appropriate AIR BAG RESTRAINT SYSTEMS article in RESTRAINTS.
  14. Using an ohmmeter, measure resistance between speed control servo/actuator harness connector C177 terminals No. 5 (Red/Yellow wire) and No. 6 (Red/Blue wire), while pressing speed control actuator SET/ACCEL switch. If resistance is 640-720 ohms, go to next step. If resistance is not 640-720 ohms, go to step  16.
  15. Turn ignition switch to ON position. Using a voltmeter, measure voltage between speed control servo/actuator harness connector C177 terminals No. 5 (Red/Yellow wire) and No. 10 (Blue wire), while pressing speed control actuator ON switch. If voltage is more than 10 volts, go to step  19. If voltage is 10 volts or less, replace speed control switch and retest system operation. See SPEED CONTROL SWITCHES  under REMOVAL & INSTALLATION.
  16. Turn ignition switch to LOCK position. Disconnect air bag sliding contact harness connector C248. Connector is located under lower steering column shroud. Using an ohmmeter, measure resistance of Red/Yellow wire between air bag sliding contact harness connector C248 (male side) and speed control servo/actuator harness connector C177 terminal No. 5. If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, repair open in Red/Yellow wire and retest system operation.
  17. Using an ohmmeter, measure resistance of Red/Blue wire between air bag sliding contact harness connector C248 (male side) and speed control servo/actuator harness connector C177 terminal No. 6. If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, repair open in Red/Blue wire and retest system operation.
  18. Disconnect speed control switch harness connector C269. Measure resistance between speed control switch harness connector C269 terminals No. 1 and 2. See Fig 4. Press speed control actuator SET/ACCEL switch. If resistance is 640-720 ohms, replace air bag sliding contact and retest system operation. See appropriate AIR BAG RESTRAINT SYSTEMS article in RESTRAINTS. If resistance is not 640-720 ohms, replace speed control switch and retest system operation. See SPEED CONTROL SWITCHES  under REMOVAL & INSTALLATION.
  19. Test drive vehicle and observe speedometer operation. If speedometer operates properly, go to next step. If speedometer does not operate properly, repair speedometer as necessary. See ANALOG INSTRUMENT PANELS - ESCORT & ZX2 article.
  20. Turn ignition switch to LOCK position. Remove speed control servo/actuator cable from speed control servo/actuator. Inspect cable by pulling end of cable and observing throttle movement. Replace cable if broken or binding, and retest system operation. Repair throttle body linkage if necessary, and retest system operation. See SPEED CONTROL SERVO/ACTUATOR CABLE  under REMOVAL & INSTALLATION. If cable is okay, replace servo/actuator and retest system operation.
Fig 1: Identifying Speed Control Servo/Actuator Harness Connector C177 Terminals
G96B29331Courtesy of FORD MOTOR CO.
Fig 2: Testing Clutch Pedal Position Switch & Deactivator Switch
G00032174Courtesy of FORD MOTOR CO.
Fig 3: Identifying Clutch Pedal Position Switch Harness Connector C292 Terminals
G00032173Courtesy of FORD MOTOR CO.
Fig 4: Identifying Speed Control Switch Harness Connector C269 Terminals
G98A00398Courtesy of FORD MOTOR CO.
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