Pinpoint Test H: Insufficient Air Conditioning (A/C) Cooling - Auxiliary System

Climate Control System

Pinpoint Test H: Insufficient Air Conditioning (A/C) Cooling - Auxiliary System

Normal Operation

Under normal operation, the auxiliary A/C system provides adequate cooling based on the position of the function selector switch.

This pinpoint test is intended to diagnose the following:

- Thermostatic Expansion Valve (TXV)

- Leaking or restricted vacuum hose

- Vacuum control motor

- Stuck or bound linkage or door

PINPOINT TEST H : INSUFFICIENT AIR CONDITIONING (A/C) COOLING - AUXILIARY SYSTEM

H1 CHECK THE MODE DOOR OPERATION

- Ignition OFF.

- Remove the rear lower body side trim panel.

- Ignition ON.

- With the engine running, cycle the function selector switch between FLR and NORM A/C or MAX A/C.

- Check the mode door for operation between the heater core and evaporator core positions.

Does the mode door operate correctly?

Yes
CHECK the TXV (Thermostatic Expansion Valve) for correct operation. INSTALL a new valve if necessary. TEST the system for normal operation.

No
GO to H2.

H2 CHECK FOR SOURCE VACUUM

- Ignition OFF.

- Disconnect: Auxiliary Vacuum Control Motor.

- Connect the vacuum pump to the vacuum supply hose.

- Ignition ON.

- With the engine running, cycle the function selector switch from FLR to NORM A/C or MAX A/C.

- Measure the supply hose vacuum.





Is the vacuum between 61-71 kPa (18-21 in-Hg)?

Yes
GO to H3.

No
LOCATE the vacuum hose restriction or leak. REPAIR the vacuum hose as necessary. TEST the system for normal operation.

H3 CHECK THE VACUUM CONTROL MOTOR

- Ignition OFF.

- Carry out a vacuum leak test on the auxiliary vacuum control motor.
- Connect the vacuum pump to the auxiliary vacuum control motor.

- Apply 61-71 kPa (18-21 in-Hg) of vacuum to the auxiliary vacuum control motor.

- Check for a vacuum drop.






Does the vacuum drop?

Yes
INSTALL a new vacuum control motor. TEST the system for normal operation.

No
CHECK for a sticking mode door and REPAIR as necessary. TEST the system for normal operation.