Preliminary Checks - HVAC

VDOT A/C System Description

The V7 compressor is a variable displacement compressor that matches the air conditioning demand by changing the compressor stroke, instead of cycling the compressor clutch. A control valve located in the rear head of the compressor senses the low side pressure and causes the compressor mechanism to stroke. Because the V7 compressor always runs and the system does not cycle, these diagnostic procedures differ from those used for fixed displacement systems.

Preliminary Checks

- Check the A/C fuse and replace as necessary.

- Check the A/C blower operation and repair as necessary.

- Check the clutch coil electrical connection and repair as necessary.

- Check the drive belt and replace if damaged or missing.

- Check the operation of the cooling fans and repair as necessary.

- Check the condenser for restricted air flow and clean as necessary.

Note: The A/C system is operating properly if the discharge air temperature and compressor pressures are equal to those in the System Performance Test (V7 Compressor Pressure Test).

Note: Refer to the following Insufficient Cooling Diagnostic Tables when you are diagnosing VD0T A/C system insufficient cooling complaints.
Testing and Inspection