GMC chervolet camaro 1999 Service Manual page 119

1 ·28 HVAC System - Manual
HVAC
VDOT A/C System Diagnosis
Preliminary Checks
• Inspect the A/C fuse. Replace as necessary.
The V5 and V7 compressors are variable displacement
compressors. The V5 and V7 compressors match
• Inspect the A/C blower operation. Repair/replace
(
as necessary.
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.
• 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 following tables when you are diagnosing
VDOT A/C system insufficient cooling complaints.
VDOT Refrigerant Charge
Step Action Value(s) Yes No
DEFINITION: The A/C system is blowing warm air. Check the refrigerant for a low charge.
Were you sent here from the VDOT Diagnostic Go to the VDOT
1 System Check?
-
System
Go to Step2 Performance table
With the ignition in the OFF position, connect the A/C
Go to the
2
gauges.
345 kPa
Compressor
Are the high and low side pressures equal to (or) above
(50 psi)
Clutch
the value specified? Engagement table Go to Step 3
1. Add 0.45 kg (1 lb of R-134a).
3
2. Check the system for leaks.
-
Is there a leak? Go to Step 6 Go to Step 4
4
Are the high and low side pressures within the 69-345 kPa
specified range? (10-50 psi) System OK Go to Step 5
5
Repair the leak.
-
-
Is the repair complete? Go to Step 6
Recover and recharge the A/C system. Refer to
Go to the
6
Refrigerant Recovery and Recharging
345 kPa
Compressor
Are the high and low side pressures above the value
(50 psi)
Clutch
specified? System OK
Engagement table
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