Diagnosis

(1) Procedures

Before an accurate evaluation of the system's operation can be made the following steps must have been accomplished:

1) Verification or Complaint

There are two steps in this process; 1) perform a complete operational check of the air source, blower motor, air mix, air discharge and control system; 2) complete a performance test and write down the results.

2) Isolation of Problem Area

Compare the data collected against the factory standards and decide a course of action.

3) Verification of Problem

Combine the "touch and feel" method, specific component test and the factory diagnosis charts to determine the exact cause of the problem.

4) Verification of Repair

After repairs are completed, perform both the operational check and performance test to verify system performance.

(2) Testing

Prior to performing any specific system test, establish the following operating conditions:

1) Start engine and allow to reach operating temperatures

2) Engine speed at 1500 RPM

3) A/C operating

4) Front windows down

5) Hood open

6) Air source for evaporator - recirculation (interior air)

7) Blower speed - high (general the 4th position)

8) A/C operates for a minimum of ten minutes

If the ambient temperature is below 60F; or the evaporator intake air is below 60F:

1) Close windows and adjust temperature to full beat. This will increase the evaporator beat load.

2) Reduce the air flow through the condenser. This will reduce the amount of heat transfer, increasing discharge pressure.