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EATC System Functional Test

WARNING: This page is about a different car, the 1994 Lincoln Mark VIII. However, it is still accessible from the selected car via links, so may be relevant.
NOTE: Perform this test if self-diagnostic system indicated no DTCs and fault is present.
  1. Ensure engine is cold and in-vehicle temperature is greater than 50°F (10°C). Turn ignition on. Press AUTOMATIC button and set temperature display to 90°F. If control module lights, go to next step. If control module does not light, go to DIAGNOSIS WHEN EATC SELF-DIAGNOSTICS INDICATE NO PROBLEMS FOUND  .
  2. Verify blower motor does not come on when engine temperature is less than 120°F (49°C). If blower motor does not come on, go to next step. If blower motor comes on, go to TEMPERATURE CONTROL LOCK-OUT VALVE & SWITCH ASSEMBLY  under TESTING.
  3. Start engine. Ensure coolant temperature is greater than 120°F (49°C). Set temperature display to 75°F. If blower motor comes on, go to next step. If blower motor does not come on, go to BLOWER SPEED CONTROLLER (BSC) & PULSE WIDTH MODULATOR (PWM)  .
  4. Rotate blower thumbwheel fully up. If blower motor goes to high speed, go to next step. If blower motor does not go to high speed, go to BLOWER SPEED CONTROLLER (BSC) & PULSE WIDTH MODULATOR (PWM)  .
    NOTE: Before going to step 5), check battery voltage. If voltage reading is less than 10 volts, check charging system.
  5. Rotate blower thumbwheel fully down. If blower motor goes to low speed, go to next step. If blower motor does not go to low speed, go to BLOWER SPEED CONTROLLER (BSC) & PULSE WIDTH MODULATOR (PWM)  .
  6. Press defrost button. Verify air is discharged from defroster nozzle with a small amount of air bled through side window demisters. Also, verify fresh/recirculated air door is in fresh air position. If air discharge and fresh/recirculated air door position is correct, go to next step. If air is not discharged through defroster or side window demisters, go to VACUUM SYSTEM DIAGNOSIS  .
  7. Press FLOOR button. If air is discharged through floor air ducts, go to next step. If air is not discharged through floor air ducts, go to VACUUM SYSTEM DIAGNOSIS  .
  8. Press VENT button. If air is discharged through panel ducts, go to next step. If air is not discharged through panel ducts, go to VACUUM SYSTEM DIAGNOSIS  .
  9. Ensure ambient temperature is more than 50°F (10°C). Press MAX A/C button. If door is not in recirculated air position, go to VACUUM SYSTEM DIAGNOSIS  . If fresh/recirculated air door is in recirculated air position, go to next step.
  10. Press VENT button again. If "VENT" is displayed and A/C compressor clutch turns off, go to next step. If "VENT" is not displayed and A/C compressor clutch remains on, go to NO OR INCORRECT A/C COMPRESSOR CLUTCH OPERATION  .
  11. Press MAX A/C button again. If "MAX A/C" is displayed and A/C compressor clutch comes on, go to next step. If A/C compressor clutch remains off, go to NO OR INCORRECT A/C COMPRESSOR CLUTCH OPERATION  .
  12. Press AUTOMATIC button. If "AUTO" is displayed, go to DIAGNOSIS WHEN EATC SELF-DIAGNOSTICS INDICATE NO PROBLEMS FOUND  . If "AUTO" is not displayed, replace EATC module.
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