Functional Test/Check

Fig. 8 Main A/C Functional Test:

Fig. 9 Rear A/C Functional Test (Part 1 0f 3):

Fig. 9 Rear A/C Functional Test (Part 2 0f 3):

Fig. 9 Rear A/C Functional Test (Part 3 0f 3):

The air conditioning system can not be tested properly unless the ambient temperature is at least 60 degrees F. Performance of the rear A/C can be affected by an inoperative auxiliary heater water shutoff valve. The valve is designed to close and keep all hot engine coolant from entering the evaporator and rear blower module during any Upper or Cool mode/temperature range. The following procedure will help to pinpoint the nature of the problem, refer to Figs. 8 and 9, for main and rear A/C functional test chart.

1. Allow engine to reach operating temperature.
2. Ensure air flow around radiator and A/C condenser is not restricted.
3. Check for leaks and kinks in A/C hoses and pipes.
4. Check for compressor clutch slippage and proper drive belt tension.
5. Engagement of compressor indicates electrical circuits are functioning properly.
6. On systems with accumulator, using your hand, feel temperature of evaporator inlet pipe and accumulator surface. If they are not equal, this would indicate a partially charged system.
7. On systems with receiver/dryer, using your hand, feel inlet and outlet pipes of evaporator. Inlet temperature of evaporator should be hot and outlet cold. If inlet is cooler than outlet or if inlet pipe is frosted over, a low refrigerant condition exists.