General Information - VDOT A/C System

VDOT A/C System Diagnosis


The V5 and V7 compressors are variable displacement compressors. The V5 and V7 compressors match the air conditioning demand by changing the compressor stroke instead of cycling the compressor clutch. A control valve is located in the rear head of the compressor. The control valve completes the following functions:
^ Senses the low side pressure.
^ Causes the compressor mechanism to change stroke.

Because the compressor always runs and the system does not cycle, these diagnostic procedures differ from procedures that are used for fixed displacement systems.

Preliminary Checks
^ Inspect the A/C fuse. Replace as necessary.
^ Inspect the A/C blower operation. Repair/replace as necessary.
^ Inspect the clutch coil electrical connection. Repair/replace as necessary.
^ Inspect the drive belt. Replace the drive belt if it is damaged or missing.
^ Inspect the operation of the cooling fans. Repair/replace as necessary.
^ Inspect the condenser for restricted air flow. Clean the condenser as necessary.

The A/C system is operating properly if the discharge air temperature and compressor pressures are equal to those in the System Performance Test Refer to the VDOT tables when you are diagnosing VDOT A/C system insufficient cooling complaints.