Hummer H1 (2002+). Manual - part 183
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Heating/Ventilation/Air Conditioning (HVAC) 11-11
®
05745159
A/C Pressure Test Diagnosis
Condition
Possible Cause
Correction
Low Side High
High Side High
(Discharge Air Warm -
Discharge Line Warm to
Hot)
1.
Condenser fins obstructed or distorted.
1.
Clear obstruction with water spray and
compressed air. Straighten distorted fins
with tool J–36847 or equivalent.
2.
System overcharged.
2.
Recover excess charge with A/C service
cart J–39500-A.
3.
Air in system.
3.
Evacuate and recharge system.
4.
Expansion valve failed.
4.
Replace valve.
5.
Condenser restricted.
5.
Replace condenser. Evacuate and recharge
system.
6.
Compressor drive belt slipping.
6.
Replace belt or belt tensioner as needed.
Low Side High
High Side High
(Discharge Air Slightly
Cool - Discharge Line
Cool)
1.
Air and moisture in system.
1.
Discharge system. Replace receiver/dryer
and evacuate - recharge system.
2.
Leak at A/C line of 1/2 ounce or less.
2.
Locate with D-Tek leak tester. Recharge
system and verify proper operation.
Low Side Low
High Side Low
1.
System low on refrigerant.
1.
Add refrigerant and leak test system. Cor-
rect leak source and recharge as needed.
NOTE:
If leak was large, check compres-
sor oil level also and correct as needed.
2.
Expansion valve failed.
2. Replace valve, then evacuate and recharge
system.
Low Side High
High Side Low
1.
Internal leak in compressor
1.
Replace compressor and evacuate -
recharge system.
2.
Expansion
valve
failure.
2.
Discharge system. Replace valve and
recharge system.
3.
Drivebelt slip.
3.
Replace belt.
Low Side Low
High Side High
1.
Expansion valve failed.
1.
Discharge system. Replace valve and
recharge.
2.
A/C hose constricted, plugged.
2.
Check hose for kinks. Replace hose if
plugged and evacuate - recharge system.
3.
Receiver/Dryer restricted or has failed.
3.
Evacuate system. Replace receiver/dryer
and recharge system.
4.
Condenser problem (blocked, damaged).
4.
Evacuate system. Replace condenser and
recharge system.
Low Side and High Side
Normal But Cooling is
Inadequate
1.
Air and/or moisture in system.
1.
Leak test system. Repair leaks if neces-
sary. If leaks are not evident, evacuate and
recharge system.
2.
Receiver/Dryer fault.
2.
Evacuate system, replace receiver/dryer
and recharge system.