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Test A: Speed Control Is Inoperative

  1. Check For Power & Ground To Speed Control Servo/Actuator  - Turn ignition off. Disconnect speed control servo/actuator connector C177 (located on left front side of engine compartment). Turn ignition switch to RUN position. Using a voltmeter, check voltage between speed control servo/actuator connector C177 terminals No. 7 and 10. See Fig 1 . If voltage is more than 10 volts, go to step 4). If voltage is 10 volts or less, go to next step.
  2. Check Fuse  - Turn ignition off. Check instrument panel fuse block fuse No. 1 (10-amp). If fuse is okay, go to next step. If fuse is not okay, replace fuse and retest system operation. If fuse fails again, check for short to ground in Yellow wire between instrument panel fuse block and speed control servo/actuator. Repair as necessary and retest system operation.
  3. Check Speed Control Servo/Actuator Ground Circuit  - Using an ohmmeter, check resistance between ground and speed control servo/actuator connector C177 terminal No. 10. See Fig 1 . If resistance is less than 5 ohms, repair open in Yellow wire between instrument panel fuse block and speed control servo/actuator. Retest system operation. If resistance is 5 ohms or more, repair open in Blue wire between speed control servo/actuator and ground.
  4. Check Stoplight Operation  - Check stoplight operation while pressing brake pedal. If stoplights operate properly, go to next step. If stoplights do not operate properly, see appropriate EXTERIOR LIGHTS wiring diagram in SYSTEM WIRING DIAGRAMS article in the WIRING DIAGRAMS section to continue diagnosis.
  5. Check Brake Circuit  - Using an ohmmeter, check resistance between speed control servo/actuator connector C177 terminals No. 4 and 10. If resistance is less than 20 ohms, go to step 8). 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 Green wire between speed control servo/actuator and Brake Pedal Position (BPP) switch. Retest system operation.
  6. Check Clutch Pedal Position (CPP) Switch  - Ensure ignition is off. Disconnect CPP switch connector C292 (located on top of clutch pedal support). Using an ohmmeter, check resistance between CPP switch terminals (switch side). 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.
  7. Check Green Wire For Open  - Ensure ignition is off. Disconnect BPP switch connector C245 (located on top of brake pedal support). Using an ohmmeter, check resistance in Green wire between CPP switch connector C292 and BPP switch connector C245. If resistance is less than 5 ohms, repair White or Green wire between speed control servo/actuator and CPP switch. Retest system operation. If resistance is 5 ohms or more, repair open in Green wire between CPP switch and BPP switch. Retest system operation.
  8. Check Deactivator Switch Input To Speed Control Servo/Actuator  - Ensure ignition is off. Using a voltmeter, check voltage between speed control servo/actuator connector C177 terminals No. 9 and 10. See Fig 1 . If voltage is 10 volts or less, go to next step. If voltage is more than 10 volts, go to step 11).
  9. Check Deactivator Switch  - Ensure ignition is off. Disconnect deactivator switch connector C208 (located on top of brake pedal support). Using an ohmmeter, check resistance between deactivator switch terminals (switch side). 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.
  10. Check For Power To Deactivator Switch  - Using a voltmeter, check voltage between ground and deactivator switch 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. Retest system operation. If voltage is 10 volts or less, repair Green/White wire between instrument panel fuse block and deactivator switch. Retest system operation.
  11. Check Red/Yellow Wire For Short To Power  - Ensure ignition is off. Using a voltmeter, check voltage between speed control servo/actuator connector C177 terminals No. 5 and 10. See Fig 1 . If voltage is indicated, go to next step. If no voltage is indicated, go to step 14).
  12. Check For Stuck Speed Control Switch  - Disconnect speed control switch connector C269 (located in steering wheel, under air bag module). Turn ignition switch to RUN position. Using a voltmeter, check voltage between speed control servo/actuator connector C177 terminals No. 5 and 10. See Fig 1 . If voltage is indicated, go to next step. If no voltage is indicated, replace speed control switches and retest system operation.
  13. Check Red/Yellow Wire For Short To Power  - Ensure ignition is off. Disconnect air bag sliding contact connector C248 (located under steering wheel). Turn ignition to RUN position. Using a voltmeter, check voltage between speed control servo/actuator connector C177 terminals No. 5 and 10. See Fig 1 . If voltage is indicated, repair short to power in Red/Yellow wire between air bag sliding contact and speed control servo/actuator. Retest system operation. If no voltage is indicated, replace air bag sliding contact and retest system operation.
  14. Check Speed Control Switch SET/ACCEL Operation  - Using an ohmmeter, check resistance between speed control servo/actuator connector C177 terminals No. 5 and 6 while pressing speed control 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. Check Speed Control Switch ON Operation  - Turn ignition switch to RUN position. Using a voltmeter, check voltage between speed control servo/actuator connector C177 terminals No. 5 and 6 while pressing speed control 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.
  16. Check Red/Yellow Wire For Open  - Ensure ignition is off. Disconnect air bag sliding contact connector C248 (located under steering wheel). Using an ohmmeter, check resistance in Red/Yellow wire between air bag sliding contact connector C248 (male side) and speed control servo/actuator 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. Check Red/Blue Wire For Open  - Using an ohmmeter, check resistance in Red/Blue wire between air bag sliding contact connector C248 (male side) and speed control servo/actuator 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. Check Air Bag Sliding Contact  - Disconnect speed control switch connector C269 (located in steering wheel, under air bag module). Using an ohmmeter, check resistance between speed control switch connector C269 (female side) terminals No. 1 and 2 while pressing speed control SET/ACCEL switch. See Fig 2 . If resistance is 640-720 ohms, replace air bag sliding contact and retest system operation. If resistance is not 640-720 ohms, replace speed control switch and retest system operation.
  19. Check Speedometer Operation  - Test drive vehicle and observe speedometer operation. If speedometer operates properly, go to next step. If speedometer does not operate properly, see appropriate INSTRUMENT PANELS article to continue diagnosis.
  20. Check Speed Control Servo/Actuator Cable & Throttle Body Linkage  - Ensure ignition is off. 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. Retest system operation. If cable is okay, replace servo/actuator and retest system operation.
Fig 1: Speed Control Servo/Actuator Connector C177 Terminals
G96B29331Courtesy of FORD MOTOR CO.
Fig 2: Speed Control Switch Connector C269 Terminals
G98A00398Courtesy of FORD MOTOR CO.
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