Electronic Climate Control

1. Verify the customer concern by operating the EATC system.
2. Visually inspect the Electronic Automatic Temperature Control (EATC) system for obvious signs of mechanical and electrical damage:

Mechanical
- A/C Compressor Drive Belt
- A/C Clutch
- Vacuum Lines
- Discharged A/C System
- Refrigerant Lines
- Vacuum Control Motor

Electrical
- Fuse(s)
- Blower Motor
- A/C Compressor
- Cooling Fan
- EATC
- Circuitry
- Electrical Connectors

3. If the concern is not visually evident, perform the system self-test. Reading and Clearing Diagnostic Trouble Codes

NOTE:
- To prevent a situation where defrost cannot be obtained, the air handling system is designed to provide defrost when no vacuum is applied to any of the three vacuum control motors. Instead, a leak in the vacuum control circuit will send all air flow to the defroster outlets. This condition may occur during acceleration (slow leak), may exist at all times (large leak), or may exist only when specific functions are selected, indicating a leak in that portion of the circuit.
- The vacuum hoses used in the passenger compartment control circuit are constructed from PVC plastic material. The vacuum hoses used in the engine compartment are constructed of Hytrel. Because of the materials used, the vacuum hoses should never be pinched off during diagnosis to locate a leak. Use a vacuum pump to locate vacuum leaks.