FixVault
Home › Lincoln › 1998 › Mark VIII Base › Repair and Diagnosis › Accessories & Equipment › Cruise Control Systems › System Testing › Test F: Speed Control Inoperative - No Flash Codes

Test F: Speed Control Inoperative - No Flash Codes

  1. Check For Voltage To Servo/Actuator  - Turn ignition off. Disconnect speed control servo/actuator connector C103 (located behind left headlight). Turn ignition switch to RUN position. Using a voltmeter, check voltage between ground and speed control servo/actuator connector C103 terminal No. 7. See Figure . If voltage is 10 volts or less, go to next step. If voltage is more than 10 volts, go to step 3).
  2. Check Fuse  - Turn ignition off. Check instrument panel fuse block fuse No. 34 (15-amp). If fuse is okay, check Red/Black wire between instrument panel fuse block and speed control servo/actuator for faults. Repair as necessary and perform SELF-DIAGNOSTIC TEST. If fuse is blown, replace fuse. Perform SELF-DIAGNOSTIC TEST. If fuse fails again, repair short to ground in Red/Black wire between instrument panel fuse block and speed control servo/actuator. Perform SELF-DIAGNOSTIC TEST.
  3. Check Servo/Actuator Ground Circuit  - Ensure ignition is off. Using an ohmmeter, check resistance between ground and speed control servo/actuator connector C103 terminal No. 10. See Figure . If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, repair Black wire between speed control servo/actuator and ground. Perform SELF-DIAGNOSTIC TEST.
  4. Check Speed Control Indicator Circuit  - Turn ignition switch to RUN position. Using a voltmeter, check voltage between ground and speed control servo/actuator connector C103 terminal No. 1. See Figure . If voltage is more than 10 volts, go to next step. If voltage is 10 volts or less, go to appropriate INSTRUMENT PANEL article to continue diagnosis.
  5. Check Speed Control ON Switch Operation  - Turn ignition off. Using a voltmeter, check voltage between ground and speed control servo/actuator connector C103 terminal No. 5 while pressing and releasing speed control ON switch. See Figure . If voltage is more than 10 volts with ON switch pressed and zero volts with switch released, go to next step. If voltage is not as specified, go to step 8).
  6. Check Speed Control Switch  - Ensure ignition is off. Using an ohmmeter, check resistance between speed control servo/actuator connector C103 terminals No. 5 and 6 while pressing speed control OFF switch. If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, go to step 9).
  7. Check Speed Control Switch Circuitry  - Using an ohmmeter, check resistance between speed control servo/actuator connector C103 terminals No. 5 and 6 while pressing speed control SET/ACCEL switch. See Figure . If resistance is 612-748 ohms, replace speed control servo/actuator and perform SELF-DIAGNOSTIC TEST. If resistance is not 612-748 ohms, replace speed control switches and perform SELF-DIAGNOSTIC TEST.
  8. Check Light Blue/Black Wire For Open  - Ensure ignition is off. Disconnect air bag sliding contact connector C295 (located near base of steering column). Using an ohmmeter, check resistance between speed control servo/actuator connector C103 terminal No. 5 and air bag sliding contact connector C295 (female side) Light Blue/Black wire terminal. If resistance is less than 5 ohms, go to step 10). If resistance is 5 ohms or more, repair open in Light Blue/Black wire and perform SELF-DIAGNOSTIC TEST.
  9. Check Orange Wire For Open  - Ensure ignition is off. Disconnect air bag sliding contact connector C295 (located near base of steering column). Using an ohmmeter, check resistance between speed control servo/actuator connector C103 terminal No. 6 and air bag sliding contact connector C295 (female side) Orange wire terminal. If resistance is less than 5 ohms, go to step 11). If resistance is 5 ohms or more, repair open in Orange wire and perform SELF-DIAGNOSTIC TEST.
  10. Check Air Bag Sliding Contact  - Disable and remove driver side air bag. See appropriate AIR BAG RESTRAINT SYSTEM article. Using an ohmmeter, check resistance between air bag sliding contact 5-pin male connector C222 terminal No. 1 and air bag sliding contact 10-pin male connector C295 terminal No. 7. See Fig 1 . If resistance is less than one ohm, replace speed control switches and perform SELF-DIAGNOSTIC TEST. If resistance is one ohm or more, replace air bag sliding contact and perform SELF-DIAGNOSTIC TEST.
  11. Check Air Bag Sliding Contact  - Disable and remove driver side air bag. See appropriate AIR BAG RESTRAINT SYSTEM article. Using an ohmmeter, check resistance between air bag sliding contact 5-pin male connector C222 terminal No. 3 and air bag sliding contact 10-pin male connector C295 terminal No. 8. See Fig 1 . If resistance is less than one ohm, replace speed control switches and perform SELF-DIAGNOSTIC TEST. If resistance is one ohm or more, replace air bag sliding contact and perform SELF-DIAGNOSTIC TEST.
Fig 1: Checking Air Bag Sliding Contact
G98B00399Courtesy of FORD MOTOR CO.
About FixVault