LEMON Manuals: Even more car manuals for everyone: 1960-2025
Home >> Mercury >> 1994 >> Capri Base, Standard >> Repair and Diagnosis >> Accessories & Equipment >> Cruise Control Systems >> Testing >> Speed Control Inoperative
April 5, 2026: LEMON Manuals is launched! Read the announcement.

Speed Control Inoperative

  1. With ignition off, inspect STOP and METER fuses. Replace failed fuses. Turn ignition on. If fuse(s) fail again, go to next step. If fuses do not fail, go to step 3).
  2. With ignition off, locate and unplug interior fuse block connectors. Measure resistance between Green/Yellow wire and ground, and between Black/Yellow wire and ground. If resistance is less than 5 ohms, repair short circuit in wire(s). If resistance is more than 5 ohms, go to next step.
  3. Locate speed control unit. Turn ignition on. Measure voltage on Black/Yellow wire at speed control unit. If battery voltage exists, go to next step. If battery voltage does not exist, repair Black/Yellow wire.
  4. Turn ignition off. Unplug speed control module connector. Unplug stoplight switch connector. Measure resistance of White/Green wire between stoplight switch and speed control module. Measure resistance between Green/White wire and ground. If resistance is not greater than 5 ohms between connectors, and is greater than 10,000 ohms to ground, go to next step. If resistance is not as specified, repair Green/White wire.
  5. Unplug brake pressure switch connector, located on brakeline at lower rear of engine compartment. Turn ignition on. Measure voltage on Green/Yellow wire at connector. If battery voltage exists, go to next step. If battery voltage does not exist, repair Green/Yellow wire.
  6. Reconnect brake pressure switch. Measure voltage on Green/Black wire at switch connector. If battery voltage exists, go to next step. If battery voltage does not exist, replace brake pressure switch.
  7. Unplug speed control module connector. Turn ignition on. Measure voltage on Green/Black wire at connector. If battery voltage exists, go to next step. If battery voltage does not exist, repair Green/Black wire.
  8. Unplug horn relay connector. Measure voltage on Green/Yellow wire at harness connector. If battery voltage exists, go to next step. If battery voltage does not exist, repair Green/Yellow wire.
  9. Reconnect wiring harness to horn relay. Measure voltage on Green/Black wire at harness connector. If battery voltage exists, go to next step. If battery voltage does not exist, replace horn relay.
  10. Disconnect wiring at speed control switch. Measure voltage on Green/Black wire at switch connector. If battery voltage exists, go to next step. If battery voltage does not exist, repair Green/Black wire.
  11. Unplug speed control switch connector. Measure resistance between specified clockspring terminal pairs with each switch pressed. See SPEED CONTROL SWITCH TEST  table. If resistance is approximately as specified, go to next step. If resistance is not as specified, replace speed control switch.
    SPEED CONTROL SWITCH TEST

    Position Terminals Resistance
    ON GRN/BLK - BLU/WHT Less Than 5
    OFF BLU/WHT - GRN/WHT Less Than 5
    SET/ACL BLU/WHT - GRN/WHT 680
    CST BLU/WHT - GRN/WHT 120
    RSM BLU/WHT - GRN/WHT 2200
  12. Turn ignition off. Unplug speed control module connector. Unplug speed control switch connector. Measure resistance of Black/White and Green/White wires between speed control switch and speed control module. Measure resistance between the same wires and ground. If resistance is not greater than 5 ohms between connectors, and is greater than 10,000 ohms to ground, go to next step. If resistance is not as specified, repair appropriate wire.
  13. Turn ignition off. Unplug speed control module connector. Measure resistance of Black/Orange wire at harness connector and ground. If resistance is less than 5 ohms, go to TRANSAXLE DOES NOT OPERATE NORMALLY WITH SPEED CONTROL ENGAGED (4EAT ONLY). If resistance is not as specified, repair Black/Orange wire.
scientia non olet · About LEMON Manuals