For 1990-2009 cars

Most A/C system problems can be detected by a thorough visual and physical inspection of the system.

Important: The importance of this inspection cannot be stressed enough because proper heating and cooling depends upon adequate front air flow.

1. Inspect condenser to radiator seal, and rear hood seal for missing or damaged parts.
2. Inspect outer surfaces of radiator and condenser cores, to be sure air flow is not blocked by dirt, leaves, or other foreign material.
3. Inspect for kinks in hoses and lines. Also inspect for refrigerant leaks using an electronic leak detector.
4. Inspect for worn/loose drive belt or malfunctioning belt tensioner.
5. Inspect blower motor operation at all speeds.
6. With blower on high, inspect for equal distribution of air from all outlets.
7. Inspect operation of control mode knob and distribution of air from designated outlets.
8. Depress recirc button with blower on high. A noticeable increase in air flow and sound should occur. Indicator should light.
9. Start engine and run until it is up to operating temperature.
10. Inspect operation of temperature control knob and air outlet temperature from hot to cold.
11. Depress A/C button. Indicator should light. Inspect compressor for clutch engagement, slippage, or noise.
12. Inspect electric cooling fan operation and speed as determined by system temperature and pressure.
13. Turn OFF A/C. Compressor clutch should disengage.
14. If any problem is found in any of the previous steps, go to the complaint condition cause charts.