For 1990-2009 cars

Important: Review the circuit description in order to familiarize yourself with the system functions.

Refer to HVAC Blower Controls Circuit Description and HVAC Compressor Controls Circuit Description .

### Visual/Physical Inspection

• | Inspect for aftermarket devices which could affect the operation of the HVAC System. Refer to Checking Aftermarket Accessories in Wiring Systems.

• | Inspect the easily accessible or visible system components for obvious damage or conditions which could cause the symptom.

### Intermittent

Faulty electrical connections or wiring may be the cause of intermittent conditions. Refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems.

### Symptom List

Refer to a symptom diagnostic procedure from the following list in order to diagnose the symptom:

• | Blower Motor Inoperative at Any Speed

• | Blower Motor Operates at High Speed Only

• | Temperature Actuator Inoperative

• | Cooling Insufficient - Air Conditioning (A/C) System

• | Defrosting Insufficient

• | Heating Insufficient

• | Heat Excessive

• | Air Delivery Improper

• | Noise Diagnosis

• | Odor Diagnosis