Condition
Possible Causes
Correction
3. Refrigerant system
overcharged.
3. See Refrigerant System Charge in this group.
Recover the refrigerant from the refrigerant
system. Charge the refrigerant system to the
proper level, if required.
4. Air in the refrigerant
system.
4. See Refrigerant System Leaks in this group.
Test the refrigerant system for leaks. Repair,
evacuate and charge the refrigerant system, if
required.
5. Engine overheating.
5. Refer to Cooling for more information. Test the
cooling system and repair, if required.
The low side pressure is too
high, and the high side
pressure is too low.
1. Accessory drive belt
slipping.
1. Refer to Cooling for more information. Inspect
the accessory drive belt condition and tension.
Tighten or replace the accessory drive belt, if
required.
2. Faulty expansion valve.
2. See A/C Expansion Valve in this group.
Replace the expansion valve, if required.
3. Faulty compressor.
3. See A/C Compressor in this group. Replace
the compressor, if required.
The low side pressure is too
low, and the high side
pressure is too high.
1. Restricted refrigerant flow
through the refrigerant lines.
1. See Liquid, Suction, and Discharge Line in this
group. Inspect the refrigerant lines for kinks, tight
bends or improper routing. Correct the routing or
replace the refrigerant line, if required.
2. Restricted refrigerant flow
through the expansion valve.
2. See A/C Expansion Valve in this group.
Replace the expansion valve, if required.
3. Restricted refrigerant flow
through the condenser.
3. See A/C Condenser in this group. Replace the
restricted condenser, if required.
HEATER PERFORMANCE TEST
WARNING: Review safety precautions and warnings
in this group before performing this procedure
(Refer to 24 - HEATING & AIR CONDITIONING/
PLUMBING - WARNINGS) and (Refer to 24 - HEAT-
ING & AIR CONDITIONING/PLUMBING - CAUTIONS).
Failure to follow the warnings and cautions could
result in possible personal injury or death.
Check the coolant level, drive belt tension, radiator
air flow and fan operation. Start engine and allow to
warm up to normal operating temperature.
WARNING: Do not remove radiator cap when engine
is hot, personal injury can result.
If vehicle has been run recently, wait 15 minutes
before removing the radiator cap. Place a rag over
the cap and turn it to the first safety stop. Allow
pressure to escape through the overflow tube. When
the system pressure stabilizes, remove the cap com-
pletely.
MAXIMUM HEATER OUTPUT: TEST AND ACTION
Engine coolant is provided to the heater system by
two heater hoses. With the engine idling at normal
operating temperature, set the temperature control
to maximum heat, the mode control to the floor posi-
tion, and the blower in the highest speed position.
Using a test thermometer, check the temperature of
the air being discharged from the floor outlets. Com-
pare the test thermometer reading to the Heater
Temperature Reference chart.
CS
HEATING & AIR CONDITIONING
24 - 9
HEATING & AIR CONDITIONING (Continued)