A METHOD FOR DETERMINING THE CAUSE OF A MALFUNCTION IN AN AIR CONDITIONING SYSTEM

摘要

A microprocessor provides a diagnostic capability, and includes tables of acceptable values of parameters, such as air discharge temperature, suction pressure, etc., for different automobile makes and air conditioner types; provision is made for adjusting the acceptable ranges of such values due to one or more ambient factors, of which ambient relative humidity may be one. The microprocessor, after comparing actual values to acceptable value ranges of the air conditioner operating values, displays possible causes of air conditioner malfunction on a video screen. The microprocessor after determining whether the air conditioning system has a cycling or a non-cycling clutch and providing a valid set of actual system values based on whether the clutch is cycling or non-cycling, compares actual values to acceptable value ranges of the air conditioner operating values, and displays possible causes of air conditioner malfunction on a video screen. Self-testing of both the microprocessor and associated electrical elements, and of mechanical elements such as conduits, valves and a scale is performed. The operator may command the microprocessor to display, in smaller print, a relatively large volume of detailed instructional material dealing with specific checking procedures or repair.