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Home › Ford › 1992 › Probe GL, Automatic › Repair and Diagnosis › Engine Mechanical › Engine Cooling Fan › Testing › Cooling Fan Inoperative

Cooling Fan Inoperative

  1. Turn ignition on. Check 40-amp cooling fan and 15-amp engine fuses. Replace if defective. If fuses are okay, turn ignition off, and go to step 2).
  2. Disconnect Black/Red wire from cooling fan fuse and Black/White wire from engine fuse. Measure resistance on each wire between fuse panel and ground. If resistance is less than 5 ohms, repair or replace affected wire. If resistance is more than 5 ohms, go to step 3).
  3. Reconnect fuse wires. Locate low-speed cooling fan relay No. 1 and high-speed cooling fan relay No. 2 (A/T) or cooling fan relay (M/T). Turn ignition on. Measure voltage on Black/Red wire at relay connector. If voltage is less than 10 volts, repair Black/Red wire to relay. If voltage is more than 10 volts, go to step 4).
  4. Measure voltage on Black/White wire at relay connector. If voltage is more than 10 volts, go to step 5). If voltage is less than 10 volts, repair Black/White wire to relay.
  5. Turn ignition on. Ground Black/Green wire terminal at cooling fan relay (M/T) or at low-speed fan relay No. 1 (A/T) connector. Measure voltage of Blue/Yellow wire at relay connector. Remeasure voltage with Black/Green wire terminal not grounded. If voltage is less than 1.5 volts with Black/Green wire terminal not grounded and greater than 10 volts with Black/Green wire terminal grounded, go to step 6) for A/T models or step 9) for M/T models. If voltage is not as specified, replace relay in question.
  6. On A/T models, ground Blue/Red wire at relay terminal. Measure voltage (ignition on) on Blue/Black wire at cooling fan relay No. 2 (high-speed). Remeasure voltage with Blue/Red wire not grounded. If voltage is less than 1.5 volts with Blue/Red wire terminal not grounded and greater than 10 volts with Blue/Red wire terminal grounded, go to step 7). If voltage is not as specified, replace cooling fan relay No. 2 (high-speed).
  7. Turn ignition off. Measure resistance on Blue/Yellow wire between cooling relay (high-speed) and cooling fan resistor. If resistance is less than 5 ohms, go to step 8). If resistance is more than 5 ohms, repair Blue/Yellow wire.
  8. Measure resistance on Blue/Black wire between cooling fan resistor and cooling fan relay (high speed). If resistance is less than 5 ohms, go to step 10). If resistance is more than 5 ohms, repair Blue/Black wire.
  9. On M/T models, measure resistance (ignition off) of Blue/Yellow wire between cooling fan relay and cooling fan motor. If resistance is less than 5 ohms, go to step 10). If resistance is more than 5 ohms, repair Blue/Yellow wire.
  10. On all models, turn ignition off. Measure resistance of Black wire between cooling fan motor and ground. If resistance is less than 5 ohms, go to step 11). If resistance is more than 5 ohms, repair Black wire.
  11. Using a fused jumper, apply battery voltage to Blue/Black wire terminal at cooling fan motor. If motor does not run, replace defective cooling fan motor. If cooling fan motor runs, go to step 12) for A/T models or step 13) for M/T models.
  12. On A/T models, apply battery voltage to Blue/Yellow wire terminal at fan motor resistor. If cooling fan motor runs, go to step 13). If cooling fan motor does not run, replace cooling fan motor resistor.
  13. On all models, turn ignition off. Measure resistance at Black/Green wire between ECU, test connector, radiator temperature switch and low speed cooling fan relay (A/T) or condenser fan relay (M/T). If resistances are less than 5 ohms, go to step 14) for A/T models or step 15) for M/T models. If resistances are greater than 5 ohms, repair affected wire.
  14. On A/T models, measure resistance at Black/Red wire between cooling fan relay No. 2 (high-speed) and ECU, condenser fan relay, test connector and high-speed radiator temperature switch. If resistances are less than 5 ohms, go to step 16). If resistances are more than 5 ohms, repair affected wire.
  15. On M/T models, turn ignition on. Ground cooling fan motor test connector. Cooling fan motor should run. If fan motor does not run, replace radiator temperature switch.
  16. On A/T models, turn ignition on. Ground Black/Green wire terminal on cooling fan motor test connector. Cooling fan should run. If cooling fan does not run, replace low-speed radiator temperature switch. Ground Blue/Red wire terminal on test connector. Cooling fan should run. If cooling fan does not run, replace high-speed radiator temperature switch.
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