Heating and Air Conditioning: Testing and Inspection

Fig. 1 A/C Cooling Performance Chart:

Prior to performance checking, ensure all system fuses are satisfactory, ambient temperature is greater than 59°F, condenser and radiator are clean and free of obstructions, V-belts for compressor and alternator are correctly tightened, all air ducts, covers and seals are satisfactory, vehicle is not exposed to direct sunlight and engine is at operating temperature.
With engine running, set mode to AUTO and temperature to LO, set blower speed to HI and open all instrument panel outlets. Ensure compressor is driven or switches On, fresh air blower runs, radiator cooling fan runs, recirculation/fresh air flap goes into ``recirculation'' position after one minute, water valve for heating is closed, evaporator, heater and connecting piece between heater and evaporator does not draw any secondary air, air comes out of instrument panel outlets and temperature flap is in ``cooling'' position. Temperature of air coming out of center instrument panel outlets must be within tolerance on chart in Fig. 1, and depends on ambient temperature and cool down period.