EATC System Functional Test

Fig. 3 Blower Motor Diagnosis:

Engine should be warm and above 1200 RPM. Vehicle interior should be 70°-80°.
1. Set function selector to VENT position. Check blower operation in low and high. If OK, move selector to AUTO. If blower does not operate properly in all positions, correct inoperative component and proceed. Refer to Fig. 3.

Fig. 4 Automatic Temperature Preformance Chart:

2. Cycle temperature lever from 65°F-85°F and observe blower speed change and discharge temperature change. Refer to Fig. 4 to compare functions.
3. Move temperature lever back to 65°F and observe blower and temperature outputs.
4. Move function lever to NORM A/C. The fresh air/recirc door should open and the A/C compressor clutch should engage to produce colder discharge temperatures.
5. Move temperature lever to 72°F-75°F. Blower speed should reduce down to low or medium low and the discharge temperature rise to a more moderate level.