Step 1 - Preliminary Checks

Diagnostic Procedures For Variable Displacement Orifice Tube (VDOT).

The procedures in the following charts will help you diagnose V5 compressor and VDOT refrigerant system problems causing insufficient cooling.

The V5 compressor is a variable displacement compressor which matches air conditioning demand by changing its stroke, instead of cycling its clutch. A control valve located in the rear head of the compressor senses compressor low side pressure and causes the compressor mechanism to change stroke. This compressor is also equipped with a RPM triggered destroking mechanism that allows the compressor to function at reduced stroke during high RPM operation. Because the V5 compressor always runs and the system does not cycle, these diagnostic procedures differ from those used for fixed displacement systems. By using these procedures, you will avoid needlessly replacing A/C components.

STEP 1 - Preliminary Checks

Repair the following as necessary. If discharge air temperature with A/C on is normal after making the following repairs, the system is operating properly.

^ A/C fuse.
^ A/C blower operation.
^ Temperature door or cable adjustment. Move temp door knob from cold to hot. Listen for temp. door hitting (thud noise) at each end Adjust as necessary. (Cable operated temp. door only.).
^ Clutch coil connections/relay
^ Compressor belt. Replace if damaged or missing.
^ Engine cooling fan operation (both fans) and proper air flow direction.
^ Check outer surfaces of radiator and condenser cores to be sure air flow is not blocked by dirt, leaves or other foreign material Be sure. to check between the condenser and radiator as well as the outer surfaces
^ Restriction in evaporator core or condenser core, or kinks in hoses, tubes, etc.
^ Dealer Technical Bulletins for updates on A/C System.