Dual Function High Pressure Switch/High Pressure Cut-Off Switch; Low Pressure Cut-Off Switch - Dodge 2000 DURANGO Service Manual

24 - 22 HEATING AND AIR CONDITIONING
DIAGNOSIS AND TESTING (Continued)
• A faulty, obstructed or improperly installed
blend-air door.
• The temperature control cable is not connected,
or is not routed or adjusted properly.
• A faulty blower system.
• A faulty heater-A/C control.
TEMPERATURE CONTROL
If the heater outlet air temperature cannot be
adjusted with the temperature control knob on the
CONDITION
INSUFFICIENT HEATER
OUTPUT.
DUAL FUNCTION HIGH PRESSURE SWITCH/
HIGH PRESSURE CUT-OFF SWITCH
Before performing diagnosis of the dual function
high pressure switch, or the high pressure cut-off
switch, verify that the refrigerant system has the cor-
rect refrigerant charge. See Refrigerant System
Charge in the Service Procedures section of this
group for more information.
For circuit descriptions and diagrams, refer to
8W-42 - Air Conditioning/Heater in Group 8W - Wir-
ing Diagrams.
(1) Disconnect and isolate the battery negative
cable.
(2) Unplug the high pressure switch wire harness
connector from the switch on the refrigerant system
fitting.
(3) On the dual function high pressure switch,
check for continuity between terminals C and D. On
Heater Diagnosis
POSSIBLE CAUSE
1. Incorrect engine
coolant level.
2. Air trapped in engine
cooling system.
3. Incorrect engine
coolant temperature.
4. Temperature control
cable improperly installed
or not adjusted.
5. Blend-air door not
operating properly.
6. Insufficient air flow
through heater housing.
7. Improper blower motor
operation.
heater-A/C control panel, the following could require
service:
• A faulty heater-A/C control.
• The temperature control cable is not connected,
or is not routed or adjusted properly.
• A faulty, obstructed or improperly installed
blend-air door.
• An obstructed cowl air intake.
• The engine cooling system.
CORRECTION
1. Check the engine coolant level. Refer to Group 7 -
Cooling System for the procedures.
2. Check the operation of the coolant reserve/recovery
system. Refer to Group 7 - Cooling System for the
procedures.
3. Check the performance and operation of the engine
cooling system including: thermostat, water pump, fan
drive, accessory drive belt, coolant flow (plugged radiator
or heater core, plugged or kinked coolant hoses), air flow
(missing or improperly installed radiator air seals or fan
shroud). Refer to Group 7 - Cooling System for the
procedures.
4. See Temperature Control Cable in the Removal and
Installation and in the Adjustments sections of this group.
5. Check for a damaged, obstructed or improperly
installed blend-air door or seals. See Heater-A/C Housing
Door in the Removal and Installation section of this
group.
6. Remove foreign material or obstructions from cowl air
intake.
7. See Blower Motor in the Diagnosis and Testing section
of this group.
the two terminal switch, check for continuity
between both terminals of the high pressure cut-off
switch. There should be continuity. If OK, test and
repair the A/C switch sense circuit as required. If not
OK, replace the faulty switch.

LOW PRESSURE CUT-OFF SWITCH

Before performing diagnosis of the low pressure
cut-off switch, remember that lower ambient temper-
atures, below about -1° C (30° F), during cold
weather will open the switch contacts and prevent
compressor operation due to the pressure/tempera-
ture relationship of the refrigerant.
Also verify that the refrigerant system has the cor-
rect refrigerant charge. See Refrigerant System
Charge in the Service Procedures section of this
group for more information.
For circuit descriptions and diagrams, refer to Air
Conditioning/Heater in Wiring Diagrams.
DN