Heating and Air Conditioning: Testing and Inspection

Fig. 2 A/C Performance Chart:

Before performing this test a visual inspection of system should be made to ensure that system is operating efficiently and correctly. Move vehicle out of direct sunlight.
1. Connect suitable tachometer and manifold gauge set, then start engine.
2. Press auto mode button, then reset the control buttons to the max. cooling position in manual mode as follows:
a. Mode selection button in face position.
b. Temperature control button in max. cooling position.
c. Air selection button in recirculation position.
d. Blower switch in high position.
3. Run engine at 1000 RPM with A/C clutch engaged.
4. Engine should be warmed up with doors, windows and hood open.
5. Insert suitable thermometer in left center A/C outlet and operated engine for approximately 20 minutes.
6. Note discharge air temperature and refer to A/C performance temperature chart, Fig. 2. If clutch cycles, take reading before clutch disengages.