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Test A: Speed Control Is Inoperative

  1. Turn ignition switch to LOCK position. Disconnect Black 10-pin speed control servo/actuator harness connector C136. Speed control servo/actuator is located behind left front fenderwell. Turn ignition switch to RUN position. Using DVOM, measure voltage between speed control servo/actuator harness connector C136 terminals No. 7 (White/Light Blue wire) and No. 10 (Black wire). See Fig 1 . Voltage should be 10 volts or more. If voltage is not as specified, go to next step. If voltage is as specified, go to step  3 .
  2. Turn ignition switch to LOCK position. Using DVOM, measure resistance between ground and speed control servo/actuator harness connector C136 terminal No. 10 (Black wire). If resistance is more than 5 ohms, repair open in Black wire between ground and speed control servo/actuator. See WIRING DIAGRAMS  . If resistance is 5 ohms or less, repair White/Light Blue wire between speed control servo/actuator and fuse No. 17 (15-amp) in central junction box. Central junction box is located behind left side of instrument panel.
  3. Using DVOM, measure voltage between speed control servo/actuator harness connector C136 terminals No. 9 (Orange wire) and No. 10 (Black wire). Voltage should be 10 volts or more. If voltage is not as specified, go to next step. If voltage is as specified, go to step  6 .
  4. Disconnect brake pressure switch harness connector C261. Brake pressure switch is located under left side of instrument panel, near brake pedal bracket. Brake pressure switch harness connector C261 has one Orange wire and one Light Green/Red wire. Using DVOM, measure voltage between ground and brake pressure switch harness connector C261 terminal No. 1 (Light Green/Red wire). Voltage should be 10 volts or more. If voltage is as specified, go to next step. If voltage is not as specified, repair open in Light Green/Red wire between brake pressure switch and fuse No. 33 (15-amp) in central junction box. See WIRING DIAGRAMS  . Central junction box is located behind left side of instrument panel.
  5. Using DVOM, measure resistance in Orange wire between brake pressure switch harness connector C261 terminal No. 2 and speed control servo/actuator harness connector C136 terminal No. 9. If resistance is more than 5 ohms, repair open in Orange wire between brake pressure switch and speed control servo/actuator. See WIRING DIAGRAMS  . If resistance is 5 ohms or less, replace brake pressure switch. Information on replacement of brake pressure switch is not available from manufacturer.
  6. Using DVOM, measure voltage between speed control servo/actuator harness connector C136 terminals No. 5 (Light Blue/Black wire) and No. 10 (Black wire) while pressing speed control switch ON button. Voltage should be 10 volts or more. If voltage is not as specified, go to next step. If voltage is as specified, go to step  9 .
  7. Deactivate air bag. See appropriate AIR BAG RESTRAINT SYSTEMS article. Disconnect air bag sliding contact harness connector C233, located at underside of steering column. Using DVOM, measure resistance in Light Blue/Black wire between air bag sliding contact harness connector C233 terminal No. 1 and speed control servo/actuator harness connector C136 terminal No. 5. If resistance is 5 ohms or less, go to next step. If resistance is more than 5 ohms, repair open in Light Blue/Black between air bag sliding contact and speed control servo/actuator. See WIRING DIAGRAMS  .
  8. Remove driver's side air bag. See appropriate AIR BAG RESTRAINT SYSTEMS article. Disconnect speed control switch harness connector C243. Using DVOM, measure resistance between bottom of air bag sliding contact pin No. 1 (component side) and top of air bag sliding contact pin No. 3. See Fig 2 . If resistance is 5 ohms or less, replace speed control switch assembly. See REMOVAL & INSTALLATION  . If resistance is more than 5 ohms, replace air bag sliding contact.
  9. Turn ignition switch to RUN position. Using DVOM, measure voltage between speed control servo/actuator harness connector C136 terminals No. 5 (Light Blue/Black wire) and No. 10 (Black wire). If any voltage exists, go to next step. If no voltage exists, go to step  12 .
  10. Turn ignition switch to LOCK position. Disconnect air bag sliding contact harness connector C233, located at underside of steering column. Turn ignition switch to RUN position. Using DVOM, measure voltage between speed control servo/actuator harness connector C136 terminals No. 5 (Light Blue/Black wire) and No. 10 (Black wire). If no voltage exists, go to next step. If any voltage exists, repair short to voltage in Light Blue/Black wire between speed control servo/actuator and air bag sliding contact. See WIRING DIAGRAMS  .
  11. Turn ignition switch to LOCK position. Deactivate air bag system and remove driver's side air bag. See appropriate AIR BAG RESTRAINT SYSTEMS article. Disconnect speed control switch harness connector C243. Turn ignition switch to RUN position. Using DVOM connected to ground, measure voltage at air bag sliding contact connector C233 pin No. 1 (component side). If no voltage exists, replace speed control switch. If any voltage exists, replace air bag sliding contact.
  12. Turn ignition switch to LOCK position. Using DVOM, measure resistance between speed control servo/actuator harness connector C136 terminals No. 5 (Light Blue/Black wire) and No. 6 (Dark Green/Orange wire). When pressing SET/ACCEL button, resistance should be 612-748. If resistance is as specified, go to next step. If resistance is not as specified, replace speed control switch.
    13. NOTE: Ensure brake lights are operating properly before proceeding.
  13. Using DVOM, measure resistance between speed control servo/actuator harness connector C136 terminals No. 4 (Light Green wire) and No. 10 (Black wire). If resistance is 20 ohms or less, go to step  17 . If resistance is more than 20 ohms, go to next step (A/T), or go to step  15 (M/T).
  14. Check for open or high resistance in Light Green wire between speed control servo/actuator harness connector C136 terminals No. 4 and fuse No. 35 (15-amp) located in central junction box. Central junction box is located behind left side of instrument panel. See WIRING DIAGRAMS  . Check for open or high resistance in Light Green/Red wire between brake pressure switch harness connector terminal No. 1 and fuse No. 33 (15-amp) located in central junction box. Repair as necessary.
  15. Disconnect Clutch Pedal Position (CPP) switch harness connector C260. CPP switch is located on clutch pedal bracket. Using DVOM, measure resistance between ground and appropriate Light Green wire terminal at CPP switch harness connector C260. If resistance is 20 ohms or less, go to next step. If resistance is more than 20 ohms, go to step  14 .
  16. Using DVOM, measure resistance in Light Green wire between CPP switch harness connector C260 terminal No. 2 and speed control servo/actuator harness connector C136 terminal No. 4. If resistance is 5 ohms or less, replace CPP switch. See REMOVAL & INSTALLATION  . If resistance is more than 5 ohms, repair open in Light Green wire between CPP switch and speed control servo/actuator. See WIRING DIAGRAMS  .
  17. Turn ignition switch to LOCK position. Disconnect Gray 104-pin Powertrain Control Module (PCM) harness connector C294. PCM is located behind passenger's side kick panel. See Fig 4 . Connect EEC-V 104-pin Breakout Box (014-00950). Using DVOM, measure resistance in White/Orange wire between speed control servo/actuator harness connector C136 terminal No. 3 and breakout box terminal No. 68. See Fig 1 . If resistance is 5 ohms or less, go to next step. If resistance is more than 5 ohms, repair open in White/Orange wire between speed control servo/actuator harness connector C136 terminal No. 3 and Gray 104-pin PCM harness connector C294 terminal No. 68. See Fig 3 . See WIRING DIAGRAMS  .
  18. Install known good speed control servo/actuator. Test drive vehicle and check for proper speed control operation. If speed control operates properly, replace speed control servo/actuator. If speed control does not operate properly, replace PCM. See REMOVAL & INSTALLATION  .
Fig 1: Identifying Servo/Actuator Harness Connector C136 Terminals
G96B29331Courtesy of FORD MOTOR CO.
Fig 2: Testing Air Bag Sliding Contact Resistance
G99H08207Courtesy of FORD MOTOR CO.
Fig 3: Identifying PCM Harness Connector C294 Terminals
G96F31315Courtesy of FORD MOTOR CO.
Fig 4: Locating Powertrain Control Module
G00033940Courtesy of FORD MOTOR CO.
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