REFRIGERANT RECYCLING
(R-12) refrigerant is a chlorofluorocarbon (CFC)
that can contribute to the depletion of the ozone
layer in the upper atmosphere. To help protect the
ozone layer, an R-12 recycling device must be used.
Contact an automotive service equipment supplier
for refrigerant recycling equipment. Refer to the op-
erating instructions provided with the recycling
equipment for proper operation.
MANIFOLD GAUGE SET CONNECTIONS
GENERAL INFORMATION
The high pressure (discharge) (RED) hose should
be attached to the 1/4 in. discharge service port. This
port is located on the discharge line between the A/C
compressor and the condenser, or on the high pres-
sure (liquid) line. The low pressure (suction) (BLUE) hose should be
attached to the 3/8 in. suction service port. This port
is located on the air conditioning compressor, or the
suction line between the expansion valve and the
compressor.
SUCTION (LOW PRESSURE) GAUGE CONNECTION
(1) Remove the service port cap from 3/8 in. suc-
tion service port. (2) Check all valves on the equipment being used
to verify they are closed. (3) Inspect the hose gasket in the service port con-
nector at the end of the (BLUE) hose. If the gasket is
flawed, replace it. (4) Thread the hose connector onto the service
port. Quickly secure hose connector to the service
port to avoid loosing refrigerant. To disconnect suction gauge (BLUE) hose:(a) Wrap the end of hose with a shop towel.
(b) Loosen the hose connector.
(c) Push and hold the end of hose toward the ser-
vice port to keep the gasket in contact with service
port. (d) Quickly rotate the connector counterclock-
wise. When the hose connector is completely
Fig. 2 Refrigerant Charging StationÐTypical
Fig. 3 Refrigerant Recovery/Recycling StationÐTypical
Fig. 4 Manifold Gauge SetÐTypical
Ä HEATING AND AIR CONDITIONING 24 - 9
backed off, immediately point the end of hose toward
floor, as possibly trapped refrigerant in the hose will
be released.(e) Install service port cap.
DISCHARGE (HIGH PRESSURE) GAUGE CONNECTION (1) Remove the service port cap from the 1/4 in.
service port. (2) Check all valves on the equipment being used to
verify they are closed. (3) Inspect the hose gasket in the service port con-
nector at the end of the (RED) hose. If the gasket is
flawed, replace it. (4) Use a suitable (3/8 in. male to 1/4 in. female)
adapter (Fig. 5), threaded securely into the end of the
(RED) hose connector.
(5) Thread the 1/4 in. hose adapter connector onto
the service port. Quickly secure adapter connector to
service port to avoid loosing refrigerant. To disconnect the discharge gauge (RED) hose:(a) Wrap the end of hose with a shop towel.
(b) Loosen the hose connector.
(c) Push and hold the end of hose toward the
service port to keep the gasket in contact with service
port. (d) Quickly rotate the connector counterclockwise.
When the hose connector is completely backed off,
immediately point the end of hose toward floor, as
possibly trapped refrigerant in the hose will be
released. (e) Install service port cap.
EVACUATION/RECOVERY/RECYCLING/CHARGING LINE CON-
NECTION
The center manifold (YELLOW) or (WHITE) hose is
used to recycle, recover, evacuate, and charge the
refrigerant system. When the discharge or suction
valves on the manifold gauge set are opened, the
refrigerant in the system will escape through this hose. This hose should be attached to a R-12
Recovery/Recycling device. Refer to the
Recovery/Recycling devices operators manual
for procedures. For disconnection of this hose, refer to Disconnect-
ing the Discharge Gauge (RED) hose in the preced-
ing paragraphs.
TESTING FOR REFRIGERANT LEAKS
If the A/C system is not cooling properly, deter-
mine if the refrigerant system is fully charged with
R-12. Follow the procedures in the Performance Test
Procedures section of this Group. If the refrigerant
system is empty or low in refrigerant charge, a leak
at any line fitting or component seal is likely. To de-
tect a leak in the refrigerant system, perform one of
the following procedures as indicated by the symp-
toms.
EMPTY REFRIGERANT SYSTEM LEAK TEST
CAUTION: Review Safety Precautions and Warnings
in General Information section of this Group.
(1) Evacuate the refrigerant system to the lowest
degree of vacuum possible. (2) Prepare a 10 oz. refrigerant (R-12) charge to be
injected into the system. Refer to Charging Refriger-
ant System for instructions. (3) Connect and dispense 10 ozs. of refrigerant into
the evacuated refrigerant system. (4) Proceed to step two of Low Refrigerant Level
Leak Test.
LOW REFRIGERANT LEVEL LEAK TEST
Caution: Review Safety Precautions and Warnings
in the General Information section of this group.
(1) Using the refrigerant level sight glass, deter-
mine if there is any (R-12) refrigerant in the system. (2) Position the vehicle in a wind free work area.
This will aid in detecting small leaks. (3) Bring the refrigerant system up to operating
temperature and pressure. This is done by allowing
the engine to run for five minutes. (4) With the engine not running, use an Electronic
Leak Detector (or equivalent) and search for leaks.
Fittings, lines, or components that appear to be oily
usually will indicate a refrigerant leak. To inspect
the evaporator core for leaks, it is possible to insert
the leak detector probe into the recirculating air door
opening (Fig. 6).
ADDING PARTIAL REFRIGERANT CHARGE
After all leaks have been corrected and it was not
necessary to empty the refrigerant system, a partial
refrigerant charge can be added.
CAUTION:Review all Safety Precautions and Warn-
ings before attempting to add refrigerant to the sys-
tem. Do not add refrigerant to a system that is
known to have a leak.
Fig. 5 Discharge Hose Adapter
24 - 10 HEATING AND AIR CONDITIONING Ä
(11) Replace shaft hex nut. Tighten the hex nut to 37
N Im (27 ft. lbs.) torque.
(12) Check air gap with feeler gauge (Fig. 12). The
specification is 0.406-0.787 mm (0.016-0.031 inch). If
air gap is not consistent around the circumference,
lightly pry up at the minimum variations. Lightly tap
down at points of maximum variation. The air gap is determined by the spacer shims.
When installing the original or a new clutch
assembly, try the original shims first. When in-
stalling a new clutch onto a compressor that
previously did not have a clutch, use 0.040, 0.020,
and 0.005 shims from the clutch accessory sack. (13) If the air gap does not meet the specification
given, add or subtract shims as required.
COMPRESSOR SHAFT SEAL
Using a refrigerant recovery machine, remove the
refrigerant from the A/C system before replacing
shaft seal.
REMOVAL
(1) Insert the 2 pins of the front plate spanner into
any 2 threaded holes of the clutch front plate (Fig.
1). Hold clutch plate stationary. Remove hex nut
with 19 mm (3/4 inch) socket.
(2) Remove clutch front plate using puller (Fig. 2).
Align puller center bolt to compressor shaft. Thumb
tighten the 3 puller bolts into the threaded holes. (3) Turn center bolt clockwise with 19 mm (3/4
inch) socket until front plate is loosened.
Fig. 12 Check Air Gap
Fig. 1 Hex Nut Removal
Fig. 10 Tool Set Driver
Fig. 11 Front Plate Installation
Ä HEATING AND AIR CONDITIONING 24 - 41
WARNING: AVOID RADIATOR/CONDENSER FAN
BLADES WHEN WORKING IN THE RADIATOR
AREA. FAN IS CONTROLLED BY TEMPERATURE
AND CAN START ANY TIME IGNITION IS ON. PER-
SONAL INJURY CAN RESULT.
(1) Disconnect fan control switch wire connector.
(2) Using a suitable jumper wire, jump across ter-
minals in wire connector. (3) Connect a suitable continuity tester across fan
control switch terminals. (4) Start engine and set idle at 1300 rpm. The ra-
diator fan should run constantly. (5) Set the A/C controls to A/C and high blower.
(6) If the high pressure gauge reads below 1102
kPa (160 psi) there should be no continuity across
the switch terminals.
CAUTION: Do not allow engine to overheat when ra-
diator air flow is blocked.
(7) Block radiator air flow with a suitable cover to
increase the high side pressure to at least 1585 kPa
(230 psi). Electrical continuity should be detected
across the fan control switch terminals. (8) Remove cover from front of vehicle to allow
high side pressure to decrease. When pressure drops
below 1102 kPa (160 psi), continuity should cease. If fan control switch is defective, replace it.
REMOVAL AND INSTALLATION
CAUTION: Refrigerant removal is not necessary
when removing the Condenser Fan Control Switch.
However, a small amount of refrigerant will vent
from the switch port. Review the refrigerant han-
dling section of Safety Precautions and Warnings in
the General Information section of this Group.
(1) Disconnect wire connector from condenser fan
control switch. (2) Loosen and quickly rotate the switch counter-
clockwise and separate from the high pressure line
switch port. To install, reverse the preceding operation.
DIFFERENTIAL PRESSURE CUT-OUT SWITCH
DIAGNOSIS
The Differential Pressure Cut-Out (DPCO) Switch
(Fig. 3) monitors the liquid refrigerant pressure on
the liquid side of the system. The DPCO is located on
the expansion valve. The expansion valve is black in
color when a variable displacement compressor is
used. The DPCO turns off voltage to the compressor
clutch coil when liquid refrigerant pressure drops to
levels that could damage the compressor. The DPCO
is a sealed factory calibrated unit. It must be re-
placed if defective.
DPCO SWITCH DIAGNOSIS
The work area must not be below 10ÉC (50ÉF) to
test the compressor clutch circuit. (1) With gear selector in park or neutral, and park
brake set, start engine and allow to idle. (2) Raise hood and disconnect DPCO switch con-
nector boot. (3) Using a suitable jumper wire, jump across the
terminals inside wire connector boot. (4) If clutch does not engage, the wiring, fuse, re-
lay, ambient switch, or high pressure cut-off switch
can be defective. Refer to Group 8W, Wiring Dia-
grams. (5) If clutch engages, connect a suitable manifold
gauge set. Read low pressure gauge. At pressure 283
kPa (41 psi) and above, DPCO switch will complete
the clutch circuit. If the low pressure gauge reads be-
low 317 kPa (46 psi), the system is low on refrigerant
charge or empty due to a leak. Refer to Testing For
Refrigerant Leaks in the Refrigerant Service Proce-
dures section. (6) Install connector boot on switch and repeat step
number 3. If the clutch does not engage, replace the
DPCO switch.
TEMPERATURE CONTROL CABLEÐAC/AY MODELS
REMOVAL AND INSTALLATION
A Temperature Control Cable is used on non-ATC
heat or heater-A/C systems only. ATC (Automatic
Temperature Control) systems use an electrically op-
erated temperature control. Refer to the ATC section
of this Group. (1) Remove the A/C-Heater control panel assembly.
Refer to A/C-Heater Control Replacement in Group
8E Instrument Panel. Disconnect the cable attaching
flag from the A/C-heater control and remove the ca-
ble from control panel.
Fig. 3 Differential Pressure Cut-Out Switch
24 - 48 HEATING AND AIR CONDITIONING Ä
(2) Locate and disconnect the cable attaching flag
on the bottom of the A/C-heater housing behind the
floor air duct (Fig. 4).
(3) Slip cable self-adjusting clip downward from
the blend-air door crank. (4) Insert a 3/16 diameter tool (drill bit or phillips
screwdriver shank) into the crank pin access hole
and rotate the clip from the cable. To install, reverse the preceding operation.
To adjust temperature cable, position the TEMP le-
ver on the control to the cool side of its travel. Al-
lowing the self-adjusting clip to slide on the cable,
rotate the blend-air door crank counterclockwise by
hand until it stops.
TEMPERATURE CONTROL CABLEÐAA,AP,AG AND
AJ MODELS
REMOVAL AND INSTALLATION
(1) Remove heater-A/C control panel. Refer to
Switch and Panel Component Service in Group 8E,
Instrument Panel. Disconnect the attaching flag on
the control cable from the heater-A/C control panel. (2) Remove console assembly. Refer to Group 8E,
Instrument Panel. (3) Remove instrument panel lower steering col-
umn cover. Refer to Group 8E, Instrument Panel. (4) Remove the right lower instrument panel/glove
box door assembly. This assembly is clipped to the
upper instrument panel at the right upper side. (5) A/C equipped vehicles: From under the hood,
disconnect the A/C suction line mounting bracket
from the dash panel (above the expansion valve). (6) From under the hood, loosen (do not remove)
the four heater-A/C assembly to dash panel mount-
ing nuts. (7) From inside the vehicle: Remove the vertical
(heater-A/C housing) support bracket (below the
glove box). (8) Tilt the entire heater-A/C housing assembly
downward to gain access to the temperature cable. (9) Locate and disconnect the attaching flag on the
control cable at the heater-A/C housing (Fig. 5). (10) Slip the cable self-adjusting clip from the
blend-air door crank (Fig. 5). (11) Remove the cable from the vehicle.
(12) To remove the self-adjusting clip from cable
(Fig. 5): (a) Insert a 4mm (3/16 inch) diameter drill bit
(Fig. 1-Inset) into the door crank access hole. Then
rotate the clip from the cable.
To install, reverse the preceding operation.
To adjust temperature cable: Position the TEMP le-
ver on the control to the cool side of its travel. Al-
lowing the self-adjusting clip to slide on the cable,
rotate the blend-air door crank counterclockwise by
hand until it stops.
BLOWER RESISTOR BLOCK
WARNING: STAY CLEAR OF THE BLOWER MOTOR
AND RESISTOR BLOCK (HOT) DURING THE FOL-
LOWING PROCEDURES.
CAUTION: Do not operate the blower motor with the
resistor block removed from the heater-A/C hous-
ing. Air must move over the hot coils.
CAUTION: Disconnect battery before performing
this operation.
REMOVE AND INSTALL
AJ AND AG BODY
(1) Remove the instrument panel glove box and
door assembly. Refer to Group 8E Instrument Panel. (2) Remove security and lamp outage modules.
(3) Locate the blower resistor block (Fig. 6). It is
above and to the front of the glove box opening on
the dash panel. Remove the wire connector. (4) Remove the two attaching screws at the resis-
tor block.
Fig. 4 Temperature Control CableÐTypical
Fig. 5 Temperature Control CableÐTypical
Ä HEATING AND AIR CONDITIONING 24 - 49