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Home >> Ford >> 2002 >> ZX2 Standard >> Repair and Diagnosis >> Transmission >> Automatic Trans >> Shift Interlock System >> System Tests >> Pinpoint Test A (Town Car) >> Diagnostic Procedure
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Diagnostic Procedure

  1. If the shift interlock system does not release correctly, go to next step. If the shift interlock system does not lock correctly, go to step  4.
  2. Turn ignition switch to OFF position. Disconnect shift interlock actuator harness connector. Apply the brake pedal. Measure the voltage between the shift interlock actuator harness connector terminal No. 1 and ground. See Figure. Is the voltage greater than 10 volts? If so, replace shift interlock actuator and test the system for normal operation. See SHIFT INTERLOCK ACTUATOR  under REMOVAL & INSTALLATION. If not, go to next step.
  3. Apply the brake pedal. Measure the voltage between fuse No. 20 (7.5-amp) and ground. See Fig 1. Is the voltage greater than 10 volts? If so, repair open in Red/Light Green wire, reconnect all components and test the system for normal operation. If not, repair open in Light Green wire, then reconnect all components and test the system for normal operation.
  4. Turn ignition switch to OFF position. Disconnect shift interlock actuator harness connector. Turn ignition switch to ON position. Measure the voltage between the shift interlock actuator harness connector terminal No. 3 and ground. See Figure. Is the voltage greater than 10 volts? If so, go to next step. If not, repair open in White/Violet wire, then reconnect all components and test the system for normal operation.
  5. Measure the resistance between the shift interlock actuator harness connector terminal No. 2 and ground. SeeFigure . Is the resistance less than 5 ohms? If so, replace shift interlock actuator. See SHIFT INTERLOCK ACTUATOR  under REMOVAL & INSTALLATION. If not, repair open in Black wire, then reconnect all components and test the system for normal.
Fig 1: Measuring Voltage At Fuse No. 20
G00104248Courtesy of FORD MOTOR CO.