BLOWER MOTOR VIBRATION AND/OR NOISE
DIAGNOSIS
The resistor block supplies the blower motor with
varied voltage (low and middle speeds) or battery
voltage (high speed).
CAUTION: Stay clear of the blower motor and resis-
tor block (Hot). Do not operate the blower motor
with the resistor block removed from the heater-A/C
housing.
Refer to the Blower Motor Vibration/Noise chart
for diagnosis.
COMPRESSOR NOISE DIAGNOSIS
Excessive noise while the A/C is being used, can be
caused by loose mounts, loose clutch, or high operat-
ing pressure. Verify compressor drive belt condition,
proper refrigerant charge and head pressure before
compressor repair is performed.
If the A/C drive belt slips at initial start-up, it does
not necessarily mean the compressor has failed.
With the close tolerances of a compressor it is pos-
sible to experience a temporary lockup. The longer
the A/C system is inactive, the more likely the condi-
tion to occur.
This condition is the result of normal refrigerant
movement within the A/C system caused by temper-
ature changes. The refrigerant movement may wash
the oil out of the compressor.
EVAPORATOR PROBE TEST
The work area and vehicle must be between 16É C
(60É F) and 32É C (90É F) when testing the switch.
(1) Disconnect the three wire connector from the
evaporator probe lead located behind the glove box
(Fig. 12).
(2) Start engine and set A/C to low blower motor
speed, panel, full cool, and RECIRC.
(3) Using a voltmeter, check for battery voltage
between Pin 1 and 2. If no voltage is detected, there
is no power to the switch. Check wiring and fuses.
Refer to Group 8W, Wiring Diagrams for circuit diag-
nosis.
(4) Using a voltmeter, check for battery voltage
between Pin 1 and Pin 3. If no voltage is detected,
there is no voltage from the Powertrain Control Mod-
ule. Refer to Group 8W, Wiring Diagrams. If voltage
is OK, connect a jumper wire between Pin 1 and Pin
3. The compressor clutch should engage. If the clutch
engages, remove the jumper wire immediately and go
to Step 5. If the compressor clutch does not engage,
check the operation of the clutch and repair as nec-
essary.(5) If compressor clutch engages, connect the evap-
orator probe 3-way connector. The compressor clutch
should engage or cycle depending on evaporator tem-
perature. If OK, go to Step 6. If not OK, replace the
clutch cycling switch.
(6) The engine running and the A/C set to:
²Blower motor on low speed
²Panel position
²Full cool
²RECIRC.
Close all doors and windows. Place a thermometer in
the center discharge vent.
(7) If the clutch does not begin to cycle off between
2É C to 7É C (35É F to 45É F), verify that the evapo-
rator probe is fully installed and not loose in evapo-
rator. If it is not properly installed, install probe and
retest outlet temperature. If the evaporator probe is
properly installed, replace the clutch cycling switch.
EXPANSION VALVE
NOTE: Expansion valve tests should be performed
after compressor tests.
Liquid CO2 is required to test the expansion
valve. It is available from most welding supply facil-
ities. CO2 is also available from companies which
service and sell fire extinguishers.
Review Safety Precautions and Warnings in the
General Information section of this Group. The work
area and vehicle must be 21É to 27ÉC (70É to 85ÉF)
when testing expansion valve. To test the expansion
valve:
(1) Connect a charging station or manifold gauge
set to the refrigerant system service ports.
(2) Disconnect wire connector at low pressure cut-
off switch (Fig. 13). Using a jumper wire, jump ter-
minals inside wire connector boot.
(3) Close all doors, windows and vents to the pas-
senger compartment.
(4) Set Heater-A/C control to A/C, full heat, floor,
RECIRC. and high blower.
(5) Start the engine and hold the idle speed (1000
rpm). After the engine has reached running temper-
ature, allow the passenger compartment to heat up.
This will create the need for maximum refrigerant
flow into the evaporator.
(6) If the refrigerant charge is sufficient, discharge
(high pressure) gauge should read 965 to 2620 kPa
(140 to 380 psi). Suction (low pressure) gauge should
read 103 to 2417 kPa (15 to 35 psi). If system cannot
achieve proper pressure readings, replace the expan-
sion valve. If pressure is correct, proceed with test.
PLHEATING AND AIR CONDITIONING 24 - 11
DIAGNOSIS AND TESTING (Continued)
gauge should return to the calibrated setting of 27
kPa (8 in. Hg.). If not there is a leak in the Actuator
Feed line.
(8) If there is no leak in the Supply line, Control,
or the Actuator Feed line, the leak must be in the
Actuator itself. Connect the Vacuum hose from the
Vacuum Test Gauge directly to the Actuator to verify
the leak.
LOCATING PINCHED VACUUM LINES
The operation of the Circulation door can be
viewed by removing the blower motor and looking up
into the unit inlet. See Blower Motor Wheel and
Assembly removal and installation in this section for
service procedures.
(1) Connect the test vacuum probe to the vehicles
(Black) supply hose. Position the vacuum test gauge
so it can be viewed from the passenger compartment.
(2) Place the Mode in the Panel position and the
Circulation control in the Recirculation position.
(3) Remove the center instrument panel bezel.
(4) Remove the center vent duct.
(5) Remove the Supply (Black) vacuum line at the
control. The test gauge should drop indicating free
flow through the Supply line. If not, there is a block-
age in the Supply line.
(6) If there is no blockage in the Supply line,
reconnect it to the Control. Remove the Actuator
Feed (Red) line from the Control. The test gauge
should drop indicating free flow through the Supply
line and Control. If not the vacuum switches on the
Control are not functioning.
(7) If there is no blockage in the Supply line or the
Control, reconnect the Actuator Feed (Red) line to the
control. Remove the Actuator Feed (Red) line at the
Actuator. The Actuator vacuum port is accessible
behind and above the Glove Box. The test gauge
should drop indicating free flow through the supply
line, Control, and the Actuator Feed line. If not,
there is a blockage in the Actuator Feed line.
(8) If there is no blockage in the Supply line, Con-
trol, or the Actuator Feed line, the Actuator must
have failed. Connect the Vacuum hose from the Vac-
uum Test Gauge directly to the Actuator to verify the
Actuator has failed.
SERVICE PROCEDURES
CHARGING A/C SYSTEM
PARTIAL CHARGE
This vehicle does not have a sight glass. It is not
possible to determine the amount of (R-134a) charge
in the system. Therefore it is necessary to completely
evacuate and recover the system, and then recharge
the system fully.
EVACUATION
Before adding refrigerant, all air must be evacu-
ated from the system.
²Connect a manifold gauge set to the A/C service
ports (Fig. 16).
²Use a vacuum pump or charging station and
evacuate system to 95 kPa (28 inches Hg) for 30 min-
utes.
²Go to Charging A/C System below.
CHARGING A/C SYSTEM
The procedure below should be used to fill the
refrigerant charge in the air conditioning system.
This A/C system does not have or use a sight glass to
check or charge the system.
WARNING: REVIEW SAFETY PRECAUTIONS AND
WARNINGS IN THIS GROUP BEFORE CHARGING
THE REFRIGERANT SYSTEM.
AVOID BREATHING A/C REFRIGERANT AND
LUBRICANT VAPOR OR MIST. EXPOSURE MAY
IRRITATE EYES, NOSE AND THROAT. USE ONLY
APPROVED SERVICE EQUIPMENT MEETING SAE
REQUIREMENTS TO DISCHARGE R-134a SYSTEM.
IF ACCIDENTAL SYSTEM DISCHARGE OCCURS,
VENTILATE WORK AREA BEFORE RESUMING SER-
VICE.
R-134a SERVICE EQUIPMENT OR VEHICLE A/C
SYSTEM SHOULD NOT BE PRESSURE TESTED OR
LEAK TESTED WITH COMPRESSED AIR. MIXTURE
OF AIR and R-134a CAN BE COMBUSTIBLE AT ELE-
VATED PRESSURES. THESE MIXTURES ARE
POTENTIALLY DANGEROUS AND MAY RESULT IN
FIRE OR EXPLOSION CAUSING INJURY OR PROP-
ERTY DAMAGE.
Fig. 16 A/C Service Ports
1 ± A/C SERVICE PORTS
2 ± FILTER/DRIER
PLHEATING AND AIR CONDITIONING 24 - 17
DIAGNOSIS AND TESTING (Continued)
CAUTION: Do not overcharge refrigerant system,
as excessive compressor head pressure can cause
noise and system failure.
After the system has been tested for leaks and
evacuated, a refrigerant (R-134a) charge can be
injected into the system.
NOTE: When connecting the service equipment
coupling to the line fitting, verify that the valve of
the coupling is fully closed. This will reduce the
amount of effort required to make the connection.
(1) If using a separate vacuum pump close all
valves before disconnecting pump. Connect manifold
gauge set to the A/C service ports (Fig. 16).
NOTE: The air conditioning system in this vehicle
holds (27 oz. or 1.69 lbs.) of R-134a refrigerant.
(2) Measure refrigerant (refer to capacities). Refer
to the instructions provided with the equipment
being used.
(3) Verify engine is shut off. Open the suction and
discharge valves. Open the charge valve to allow the
refrigerant to flow into the system. When the trans-
fer of refrigerant has stopped, close the suction and
discharge valve.
(4) If all of the charge did not transfer from the
dispensing device, put vehicle controls into the fol-
lowing mode:
²Automatic transaxle in park or manual tran-
saxle in neutral
²Engine idling at 700 rpm
²A/C control set in 100 percent outside air
²Panel mode
²Blower motor ON high speed
²Vehicle windows closed
If the A/C compressor does not engage, test the
compressor clutch control circuit and correct any fail-
ure. Refer to Group 8W, Wiring Diagrams.
(5) Open the suction valve to allow the remaining
refrigerant to transfer to the system.
WARNING: TAKE CARE NOT TO OPEN THE DIS-
CHARGE (HIGH-PRESSURE) VALVE AT THIS TIME.
(6) Close all valves and test the A/C system perfor-
mance.
(7) Disconnect the charging station or manifold
gauge set. Install the service port caps.
EVACUATING REFRIGERANT SYSTEM
NOTE: Special effort must be used to prevent mois-
ture from entering the A/C system oil. Moisture in
the oil is very difficult to remove and will cause a
reliability problem with the compressor.If a compressor designed to use R-134a refrigerant
is left open to the atmosphere for an extended period
of time. It is recommended that the refrigerant oil be
drained and replaced with new oil or a new compres-
sor be used. This will eliminate the possibility of con-
taminating the refrigerant system.
If the refrigerant system has been open to the
atmosphere, it must be evacuated before the system
can be filled. Moisture and air mixed with the refrig-
erant will raise the compressor head pressure above
acceptable operating levels. This will reduce the per-
formance of the air conditioner and damage the com-
pressor. Moisture will boil at near room temperature
when exposed to vacuum. To evacuate the refrigerant
system:
NOTE: When connecting the service equipment
coupling to the line fitting, verify that the valve of
the coupling is fully closed. This will reduce the
amount of effort required to make the connection.
(1) Connect a suitable charging station, refrigerant
recovery machine, and a manifold gauge set with
vacuum pump (Fig. 17).
(2) Open the suction and discharge valves and
start the vacuum pump. The vacuum pump should
run a minimum of 45 minutes prior to charge to
eliminate all moisture in system. When the suction
gauge reads -88 kPa (- 26 in. Hg) vacuum or greater
for 45 minutes, close all valves and turn off vacuum
pump. If the system fails to reach specified vacuum,
the refrigerant system likely has a leak that must be
corrected. If the refrigerant system maintains speci-
fied vacuum for at least 30 minutes, start the vac-
uum pump, open the suction and discharge valves.
Fig. 17 Refrigerant Recovery Machine Hookup -
Typical
1 ± LOW SIDE CONNECTOR
2 ± HIGH SIDE CONNECTOR
3 ± TO MANIFOLD SET
24 - 18 HEATING AND AIR CONDITIONINGPL
SERVICE PROCEDURES (Continued)
Then allow the system to evacuate an additional 10
minutes.
(3) Close all valves. Turn off and disconnect the
vacuum pump.
(4) The refrigerant system is prepared to be
charged with refrigerant.
R-134a REFRIGERANT
This vehicle uses a refrigerant called R-134a. It is
a non-toxic, non-flammable, clear colorless liquefied
gas.
R-134a refrigerant is not compatible with R-12
refrigerant in an air conditioning system. Even a
small amount of R-12 in a R-134a system could cause
compressor failure, refrigerant oil to sludge and/or
poor performance.Never add any other type of
refrigerant to a system designed to use R-134a
refrigerant. System failure will occur.
The high pressure service port is located on the
ffilter/drier. The low pressure service port is located
on the suction line near the strut tower.
When servicing a system, it is required that an air
conditioning charging recovery/recycling machine be
used (Fig. 18). Contact an automotive service equip-
ment supplier for proper equipment. Refer to the
operating instructions provided with the equipment
for proper operation.
A manifold gauge set (Fig. 19) must also be used in
conjunction with the charging and/or recovery/recy-
cling device. Only use gauges that have not been
used for R-12. The service hoses on the gauge set
should have manual (turn wheel) or automatic back
flow valves at the service port connector ends. This
will prevent refrigerant R-134a from being released
into the atmosphere.R-134a refrigerant requires a special type of com-
pressor oil. When adding oil, make sure to use the oil
that is specified on the under hood label.
The use of R-134a will have a positive environmen-
tal impact due to it's zero ozone depletion and low
global warming impact.
SERVICING REFRIGERANT OIL LEVEL
CAUTION: The refrigerant oil used in a R-134a A/C
system is unique. Use only oils which were
designed to work with R-134a refrigerant. The oil
designated for this vehicle is ND8 PAG (polyalka-
lene glycol).
Recovery/recycling equipment will measure the
lubricant being removed. This is the amount of lubri-
cant to be added back to the system. If a new com-
pressor is being installed, drain lubricant from old
compressor, measure the amount drained and discard
old lubricant. Drain the lubricant from the new com-
pressor into a clean container. Return the amount of
lubricant measured from the old compressor, plus the
amount reclaimed from the system back into the new
compressor.
Fig. 18 Refrigerant Recovery/Recycling Station -
Typical
1 ± R-134 REFRIGERANT RECOVERY MACHINE
Fig. 19 Manifold Gauge Set - Typical
1 ± LOW PRESSURE GAUGE
2 ± HIGH PRESSURE GAUGE
3 ± VALVE
4 ± VACUUM/REFRIGERANT HOSE (YELLOW W/BLACK STRIP)
5 ± HIGH PRESSURE HOSE (RED W/BLACK STRIP)
6 ± LOW PRESSURE HOSE (BLUE W/BLACK STRIP)
7 ± VALVE
PLHEATING AND AIR CONDITIONING 24 - 19
SERVICE PROCEDURES (Continued)
BLOWER MOTOR RESISTOR
CAUTION: Stay clear of the blower motor and resis-
tor block (Hot). Do not operate the blower motor
with the resistor block removed.
REMOVAL
(1) Remove windshield wipers.
(2) Remove cowl top screen.
(3) Disconnect the resistor block wiring connector
(Fig. 22).
(4) Remove/unsnap resistor block from vehicle.
INSTALLATION
For installation, reverse the above procedures.
BLOWER MOTOR WHEEL
The blower motor wheel is only serviced with the
blower motor. The wheel and the motor are balanced
as an assembly. If the blower motor wheel requires
replacement, the blower motor must also be replaced.
Refer to blower motor for replacement procedure.
COMPRESSOR
CAUTION: Add only new lubricant when system
requires additional lubricant. Do not use old
reclaimed lubricant.
REMOVAL
The A/C compressor may be unbolted and reposi-
tioned without discharging the refrigerant system.
Discharging is not necessary if removing the com-
pressor clutch/coil assembly, engine, cylinder head, or
alternator.
WARNING: REFRIGERANT PRESSURES REMAIN
HIGH EVEN THOUGH THE ENGINE MAY BE
TURNED OFF. DO NOT TWIST OR KINK THE
REFRIGERANT LINES WHEN REMOVING A FULLY
CHARGED COMPRESSOR. SAFETY GLASSES
MUST BE WORN.
(1) Disconnect battery negative cable.
(2) Loosen and remove drive belts, refer to Group
7, Engine Cooling.
(3) Using a R-134a refrigerant recovery machine,
remove the refrigerant from A/C system. If the com-
pressor is being replaced.
(4) Disconnect compressor clutch wire lead.
(5) Remove refrigerant lines from compressor, if
necessary (Fig. 23).
(6) If system is left open place plug/cap over open
lines.
(7) Remove compressor attaching bolts (Fig. 24).
Fig. 22 Blower Motor Resistor Block
1 ± RESISTOR BLOCK
2 ± ELECTRICAL CONNECTOR
Fig. 23 A/C Compressor Lines
1 ± CONDENSER LIQUID LINE
2 ± SUCTION LINE
3 ± COMPRESSOR MANIFOLD SCREWS
4 ± COMPRESSOR
5 ± DISCHARGE LINE
24 - 22 HEATING AND AIR CONDITIONINGPL
REMOVAL AND INSTALLATION (Continued)