System Check Component Test
1. Perform EATC Self Testa. Key in run position. Turn EATC system on. Press the OFF and FLOOR buttons simultaneously and then press the automatic button within two seconds. The test may take as long as 30 seconds. When the selftest is completed, diagnostic trouble codes (DTCs) will be displayed in the digital display window to list those found during the self-test. DTCs will also be given for intermittent faults encountered during system operation. Record these DTCs. Press the blue (COOLER) button to exit self-test.
b. If DTC 888 was displayed, refer to DTC chart to find the condition. Perform the necessary diagnosis and service component(s) in question.
c. If DTC 888 was not displayed, go to the next step.
2. Check Blower Manual Override Low Speed Operation
a. Rotate the blower thumbwheel down to the stop.
b. If the blower motor switched to low speed, go to the next step.
c. If the blower motor did not switch to low speed, refer to Pinpoint Test D.
3. Check Blower Manual Override High Speed Operation
a. Rotate the blower thumbwheel up to the stop.
b. If the blower motor switched to high speed, go to the next step.
c. If the blower motor did not switch to the high speed, refer to Pinpoint Test E.
4. Verify Defrost Override Operation
a. Press the DEF button and check system discharge airflow. Airflow should be from the windshield defroster nozzle and the A/C side window demisters. Also check to be sure the heater and A/C air inlet duct door is in the outside position.
b. If the airflow is discharged from the ducts listed above, go to the next step.
c. If the airflow is not discharged from the ducts listed above, refer to Vacuum Leak Diagnosis.
5. Verify Floor Override Operation
a. Press the FLOOR button and check system discharge airflow. Discharge airflow should be from the heater floor duct.
b. If the airflow is discharged from the heater floor duct, go to the next step.
c. If the airflow is not discharged from the heater floor duct, refer to Vacuum Leak Diagnosis.
6. Verify Vent Override Operation
a. Press the VENT button and check system discharge airflow. Airflow should be from the A/C registers.
b. If the airflow is discharged from the A / C registers, go to the next step.
c. If the airflow is not discharged from the A/C registers, refer to Vacuum Leak Diagnosis.
7. Verify MAX A/C Override Operation
a. With the ambient temperature above 4°C (400 F), press the MAX A/C button. Check that the heater and A/C air inlet duct door is in the recirculate position (closed to the outside air). If the air inlet door is closed to the outside air, go to the next step.
b. If the air inlet door is not closed to the outside air, refer to Vacuum Leak Diagnosis.
8. Verify Clutch Engagement in Vent
a. Press the VENT button. "VENT" should be displayed and the A/C clutch should not engage.
b. If VENT is displayed and A/C clutch engages, diagnose compressor clutch concern.
c. If VENT is displayed and A/C clutch did not engage, go to the next step.
d. If VENT is displayed and A/C clutch engaged, check compressor air gap.
9. Verify MAX A/C Operation
a. Press the MAX A/C button again. "MAX A/C" should be displayed and the A/C clutch should engage for A/C compressor operation.
b. If MAX A/C is displayed and A/C clutch engaged, go to the next step.
c. If MAX A/C is displaced and A/C clutch is not engaged, diagnose compressor clutch concern.
10. Verify Automatic Operation
a. Press the AUTOMATIC button. The selected temperature and "AUTOMATIC" should be displayed.
b. If the selected temperature and "AUTOMATIC" are displayed, test is complete.
c. If the selected temperature and "AUTOMATIC" are not displayed, refer to Step 1 and DTC chart.