1999 DODGE NEON check engine

to 3mm (1/8 in.) below the ADD mark on the dip-
stick.
(9) Recheck the fluid level after the transaxle is at
normal operating temperature. The level should be in
the HOT range. Drive the vehicle a minimum of 10
miles.
(10) Raise the vehicle on the hoist.
(11) Check for leaks around the transaxle oil pan
sealing surfaces.
(12) Recheck the fluid level. The level should be in
the HOT range.
SEVERE USAGE SERVICE
If the vehicle exhibits any of the following symp-
toms, it is recommended that the transaxle oil and
filter be replaced.
²Transaxle oil discolored
²Transaxle oil has high mileage
²Oil feels grimy when rubbed between fingertips
²Poor shift quality
²Delayed gear engagement
²Vehicle shudder between shifts
TRANSAXLE OIL AND FILTER REPLACEMENT
This procedure involves changing the transaxle
fluid and filter, driving the vehicle for 10 miles and
changing the transaxle fluid a second time.
(1) Bring the vehicle up to normal operating tem-
perature. Drive the vehicle a minimum of 10 miles.
(2) Raise the vehicle on the hoist.
(3) Loosen the transaxle oil pan and drain the
fluid into a suitable container.
(4) Remove the pan and clean all sealant from the
pan and transaxle mating surfaces. Clean the mag-
net and the inside of the pan.
(5) Separate the filter and O-ring from the valve
body. Inspect the O-ring for cuts or improper instal-
lation. This could lead to delayed garage shifts.
(6) Install a new filter. Replace the O-ring as nec-
essary.
(7) Apply a 1/8 inch bead of Mopar RTV Sealant to
the mounting flange of the transaxle oil pan. Apply
RTV Sealant to the underside of the attaching bolts.
Attach the oil pan to the transaxle. Tighten the bolts
to 19 N²m (165 in. lbs.).
(8) Lower the vehicle and add 4 Quarts of Mopar
ATF Plus 3 Type 7176 transaxle fluid.
(9) Start the engine and allow it to idle for a min-
imum of one minute. With the parking brake applied,
press your foot on the service brake and cycle the
transaxle from park to all gear positions ending in
neutral or park.
(10) Check the transaxle fluid level and add an
appropriate amount to bring the transaxle fluid level
to 3mm (1/8 in.) below the ADD mark on the dip-
stick.(11) Recheck the fluid level after the transaxle is
at normal operating temperature. The level should be
in the HOT range. Drive the vehicle a minimum of
10 miles.
(12) Raise the vehicle on the hoist.
(13) Remove the pan and clean all sealant from
the pan and transaxle mating surfaces. Clean the
magnet and the inside of the pan.
(14) Separate the filter from the valve body to
allow additional fluid to drain from the transaxle.
Inspect the filter O-ring for any damage and replace
as necessary.
(15) After the transaxle has stopped draining,
reinstall the filter and O-ring.
(16) Apply a 1/8 inch bead of Mopar RTV Sealant
to the mounting flange of the transaxle oil pan.
Apply RTV Sealant to the underside of the attaching
bolts. Attach the oil pan to the transaxle. Tighten the
bolts to 19 N²m (165 in. lbs.).
(17) Lower the vehicle and add 4 Quarts of Mopar
ATF Plus 3 Type 7176 transaxle fluid.
(18) Start the engine and allow it to idle for a min-
imum of one minute. With the parking brake applied,
press your foot on the service brake and cycle the
transaxle from park to all gear positions ending in
neutral or park.
(19) Check the transaxle fluid level and add an
appropriate amount to bring the transaxle fluid level
to 3mm (1/8 in.) below the ADD mark on the dip-
stick.
(20) Recheck the fluid level after the transaxle is
at normal operating temperature. The level should be
in the HOT range.
FLUID DRAIN AND REFILL
(1) Raise vehicle on a hoist (See Group 0, Lubrica-
tion). Place a drain container, with a large opening,
under transaxle oil pan.
(2) Loosen pan bolts and tap the pan at one corner
to break it loose allowing fluid to drain, then remove
the oil pan.
(3) Install a new filter and gasket on bottom of the
valve body and tighten retaining screws to 5 N´m (40
inch-pounds).
(4) Clean the oil pan and magnet. Reinstall pan
using new sealant. Tighten oil pan bolts to 19 N´m
(165 in. lbs.).
(5) Pour four quarts of Mopar ATF PLUS 3 (Auto-
matic Transmission Fluid) type 7176 into the tran-
saxle filler tube.
(6) Start engine and allow to idle for at least one
minute. Then, with parking and service brakes
applied, move selector lever momentarily to each
position, ending in the PARK or NEUTRAL position.
(7) Add sufficient fluid to bring level to 1/8 inch
below the ADD mark.
PLTRANSAXLE 21 - 57
SERVICE PROCEDURES (Continued)

(8) Recheck fluid level after transaxle is at normal
operating temperature. The level should be in the
HOT region.
ALUMINUM THREAD REPAIR
Damaged or worn threads in the aluminum tran-
saxle case and valve body can be repaired by the use
of Heli-Coils. This repair consists of drilling out the
worn-out or damaged threads. Then tap the hole with
a Heli-Coil tap, and install a Heli-Coil insert into the
hole. This brings the hole back to its original thread
size.
Heli-Coil tools and inserts are readily available
from most automotive parts suppliers.
FLUSHING COOLERS AND TUBES
When a transaxle failure has contaminated the
fluid, the oil cooler(s) must be flushed. The cooler
bypass valve in the transaxle must be replaced also.
The torque converter must also be replaced with an
exchange unit. This will ensure that metal particles
or sludged oil are not later transferred back into the
reconditioned (or replaced) transaxle.
The recommended procedure for flushing the cool-
ers and tubes is to use Tool 6906A Cooler Flusher.
WARNING: WEAR PROTECTIVE EYEWEAR THAT
MEETS THE REQUIREMENTS OF OSHA AND ANSI
Z87.1±1968. WEAR STANDARD INDUSTRIAL RUB-
BER GLOVES.
KEEP LIGHTED CIGARETTES, SPARKS, FLAMES,
AND OTHER IGNITION SOURCES AWAY FROM THE
AREA TO PREVENT THE IGNITION OF COMBUSTI-
BLE LIQUIDS AND GASES. KEEP A CLASS (B) FIRE
EXTINGUISHER IN THE AREA WHERE THE
FLUSHER WILL BE USED.
KEEP THE AREA WELL VENTILATED.
DO NOT LET FLUSHING SOLVENT COME IN CON-
TACT WITH YOUR EYES OR SKIN: IF EYE CONTAM-
INATION OCCURS, FLUSH EYES WITH WATER FOR
15 TO 20 SECONDS. REMOVE CONTAMINATED
CLOTHING AND WASH AFFECTED SKIN WITH
SOAP AND WATER. SEEK MEDICAL ATTENTION.
COOLER FLUSH USING TOOL 6906A
(1) Remove cover plate filler plug on Tool 6906A.
Fill reservoir 1/2 to 3/4 full of fresh flushing solution.
Flushing solvents are petroleum based solutions gen-
erally used to clean automatic transmission compo-
nents.DO NOTuse solvents containing acids, water,
gasoline, or any other corrosive liquids.
(2) Reinstall filler plug on Tool 6906A.
(3) Verify pump power switch is turned OFF. Con-
nect red alligator clip to positive (+) battery post.
Connect black (-) alligator clip to a good ground.
(4) Disconnect the cooler lines at the transmission.NOTE: When flushing transmission cooler and
lines, ALWAYS reverse flush.
(5) Connect the BLUE pressure line to the OUT-
LET (From) cooler line.
(6) Connect the CLEAR return line to the INLET
(To) cooler line
(7) Turn pump ON for two to three minutes to
flush cooler(s) and lines. Monitor pressure readings
and clear return lines. Pressure readings should sta-
bilize below 20 psi. for vehicles equipped with a sin-
gle cooler and 30 psi. for vehicles equipped with dual
coolers. If flow is intermittent or exceeds these pres-
sures, replace cooler.
(8) Turn pump OFF.
(9) Disconnect CLEAR suction line from reservoir
at cover plate. Disconnect CLEAR return line at
cover plate, and place it in a drain pan.
(10) Turn pump ON for 30 seconds to purge flush-
ing solution from cooler and lines. Turn pump OFF.
(11) Place CLEAR suction line into a one quart
container of Mopar ATF Plus 3ttype 7176 automatic
transmission fluid.
(12) Turn pump ON until all transmission fluid is
removed from the one quart container and lines. This
purges any residual cleaning solvent from the trans-
mission cooler and lines. Turn pump OFF.
(13) Disconnect alligator clips from battery. Recon-
nect flusher lines to cover plate, and remove flushing
adapters from cooler lines.
OIL PUMP VOLUME CHECK
After the new or repaired transmission has been
installed, fill to the proper level with Mopar ATF
PLUS 3 (Type 7176) automatic transmission fluid.
The volume should be checked using the following
procedure:
(1) Disconnect theFrom coolerline at the trans-
mission and place a collecting container under the
disconnected line.
CAUTION: With the fluid set at the proper level,
fluid collection should not exceed (1) quart or inter-
nal damage to the transmission may occur.
(2) Run the engineat curb idle speed, with the
shift selector in neutral.
(3) If fluid flow is intermittent or it takes more
than 20 seconds to collect one quart of ATF, discon-
nect theTo Coolerline at the transaxle.
(4) Refill the transaxle to proper level and recheck
pump volume.
(5) If flow is found to be within acceptable limits,
replace the cooler. Then fill transmission to the
proper level, using Mopar ATF PLUS 3 (Type 7176)
automatic transmission fluid.
21 - 58 TRANSAXLEPL
SERVICE PROCEDURES (Continued)

VEHICLE SPEED SENSOR PINION GEAR
When the sensor is removed for any reason, a
NEW O-ring must be installed on its outside diame-
ter.
REMOVAL
(1) Remove harness connector from sensor. Be sure
weather seal stays on harness connector.
(2) Remove bolt securing the sensor in the exten-
sion housing.
(3) Carefully pull sensor and pinion gear assembly
out of extension housing.
(4) Remove pinion gear from sensor.
INSTALLATION
(1) To install, reverse the above procedure. Be sure
extension housing and sensor flange are clean prior
to installation. Always use a NEW sensor O-ring.
(2) Tighten bolt to 7 N´m (60 in. lbs.). Tighten
speedometer cable to 4 N´m (35 in. lbs.).
PARK/NEUTRAL STARTING AND BACK-UP LAMP
SWITCH
TEST
The park/neutral starting switch is the center ter-
minal of the three terminal switch. It provides
ground for the starter solenoid circuit through the
selector lever in PARK and NEUTRAL positions only.
(1) To test switch, remove wiring connector from
switch and test for continuity between center pin of
switch and transaxle case. Continuity should exist
only when transaxle is in PARK or NEUTRAL.
(2) Check gearshift cable adjustment before replac-
ing a switch that tests bad.
REMOVAL
(1) Unscrew switch from transaxle case allowing
fluid to drain into a container. Move selector lever to
PARK, then to NEUTRAL position, and inspect to see
the switch operating lever fingers are centered in
switch opening.
INSTALLATION
(1) Screw the switch with a new seal into tran-
saxle case and tighten to 33 N´m (24 ft. lbs.). Retest
switch with the test lamp.
(2) Add fluid to transaxle to bring up to proper
level.
(3) The back-up lamp switch circuit is through the
two outside terminals of the three terminal switch.
(4) To test switch, remove wiring connector from
switch and test for continuity between the two out-
side pins.
(5) Continuity should exist only with transaxle in
REVERSE position.(6) No continuity should exist from either pin to
the case.
TRANSAXLE
REMOVAL
NOTE: The transaxle can be removed from the
vehicle without having to remove the engine.
The transaxle and torque converter must be
removed as an assembly; otherwise, the torque con-
verter drive plate, pump bushing, or oil seal may be
damaged. The drive plate will not support a load;
therefore, none of the weight of the transaxle should
be allowed to rest on the plate during removal.
All transaxle components are serviced with the
transaxle out of the vehicle. The components that are
serviceable in the vehicle are:
²Axle shaft seals
²Back±up lamp switch
²End plate
²Extension housing
²Neutral safety switch
²Shift lever
²Transaxle oil pan
²Valve Body
²Vehicle speed sensor
(1) Disconnect the battery.
(2) Pull Power Distribution Center up and out of
its holding bracket. Set Power Distribution Center
aside to gain clearance.
(3) Remove battery heat shield and remove battery
from engine compartment. Remove battery tray from
engine compartment. Disconnect cruise control (if
equipped).
(4) Remove vehicle speed sensor wiring.
(5) Disconnect neutral safety switch and torque
converter control wiring at transaxle.
CAUTION: Pry up with equal force on both sides of
shifter cable isolator bushing to avoid damaging
cable isolator bushing.
(6) Disconnect gear shift cable end from transaxle
shift lever (Fig. 22). Remove bracket bolt at transaxle
(Fig. 23).
(7) Remove throttle pressure control cable from
lever. Then remove bracket bolts at the transaxle
(Fig. 24).
(8) Remove dipstick tube.
(9) Remove transaxle cooler lines and plug lines
(Fig. 25).
(10) Remove throttle pressure control cable sup-
port bracket bolts. Remove upper bellhousing bolts
and upper starter bolt (Fig. 26).
21 - 64 TRANSAXLEPL
REMOVAL AND INSTALLATION (Continued)

ADJUSTMENT
(1) Set parking brake.
(2) Remove floor console. Refer to Group 23, Body.
(3) Place gearshift lever in the (PARK) (P) posi-
tion.
(4) Push down on the tab and unsnap the collar at
the shifter cable to allow the cable to be adjusted
(Fig. 196).
(5) Move the gearshift lever on the transaxle to
the PARKposition.
(6) Verify the shift lever and transaxle are in the
PARK position. Rotate collar on the shift cable
adjuster end up until it seats against the plastic
housing. NOTE: If the collar will not rotate to the
fully detented lock position, rotate the collar back to
its initial unlocked position. Position the ATX in the
gated PARK position. Apply a slight load to the shift
lever, fore or aft in vehicle, while simultaneously
rotating the collar upward to the LOCK position. The
collar must seat against the plastic housing to
achieve the required detented lock position. The gear-
shift linkage should now be properly adjusted.
Check adjustment as follows:
(7) Detent position for NEUTRAL and DRIVE
should be within limits of hand lever gate stops.
(8) Key start must occur only when the shift lever
is in PARK or NEUTRAL positions.
THROTTLE PRESSURE CABLE ADJUSTMENT
PROCEDURE
The throttle pressure cable adjustment is very
important to proper transaxle operation. This adjust-
ment positions a valve which controls shift speed,
shift quality, and part throttle downshift sensitivity.
If the setting is too long, early shifts and slippage
between shifts may occur. If the setting is too short,
shifts may be delayed and part throttle downshifts
may be very sensitive.(1) Perform transaxle throttle pressure cable
adjustment while engine is at normal operating tem-
perature.
(2) Release cross-lock on the cable assembly (pull
cross-lock upward) see (Fig. 197).
(3) To ensure proper adjustment, the cable must be
free to slide all the way toward the engine, against
its stop, after the cross-lock is released.
(4) Move transaxle throttle control lever fully
clockwise, against its internal stop, and press cross-
lock downward into locked position.
The adjustment is complete and transaxle throttle
cable backlash was automatically removed.
Test cable freedom of operation by moving the
transaxle throttle lever forward (counterclockwise).
Then slowly release it to confirm it will return fully
rearward (clockwise).
No lubrication is required for any component of the
throttle cable system.
SHIFTER/IGNITION INTERLOCK SYSTEM
If ignition switch cannot be turned to the LOCK
position, with shifter in PARK, an adjustment of the
Interlock System may be required. To adjust Shifter/
Ignition Interlock System, follow procedure listed
below.
(1) Disconnect and isolate, the battery negative (-)
cable from the vehicle battery.
(2) Remove console assembly. Refer to Group 23,
Body.
(3) Remove the gearshift knob set screw and knob.
(4) Remove the screws retaining the gearshift indi-
cator bezel and remove bezel and indicator lamp.
(5) Reinstall the gearshift knob.
(6) Place shifter in PARK.
(7) Turn ignition switch to the LOCK or ACCES-
SORY position. If cable has lost its adjustment, man-
ually position cable to get key into LOCK or
ACCESSORY position. Grasp slug on interlock cable
Fig. 196 Gearshift Cable Adjustment
Fig. 197 Throttle Pressure Cable Adjuster Lock
21 - 100 TRANSAXLEPL
ADJUSTMENTS (Continued)

HEATING AND AIR CONDITIONING
CONTENTS
page page
GENERAL INFORMATION
INTRODUCTION......................... 2
SAFETY PRECAUTIONS AND WARNINGS..... 2
DESCRIPTION AND OPERATION
A/C REFRIGERANT LINES................. 3
BLOWER MOTOR RESISTOR............... 3
COMPRESSOR FRONT SHAFT SEAL......... 4
COMPRESSOR.......................... 4
CONDENSATION DRAIN TUBE.............. 4
ENGINE COOLING SSTEM
REQUIREMENTS....................... 4
EVAPORATOR PROBE..................... 4
HANDLING TUBING AND FITTINGS.......... 4
HIGH PRESSURE CUT OUT SWITCH......... 5
LOW PRESSURE CUT OFF SWITCH......... 5
SIDE WINDOW DEMISTERS............... 5
SYSTEM AIRFLOW....................... 5
SYSTEM OIL LEVEL...................... 6
VACUUM CONTROL SYSTEM............... 6
DIAGNOSIS AND TESTING
A/C PERFORMANCE TEST................. 6
BLOWER MOTOR ELECTRICAL DIAGNOSIS . . . 8
BLOWER MOTOR VIBRATION
AND/OR NOISE DIAGNOSIS.............. 8
COMPRESSOR NOISE DIAGNOSIS.......... 7
EVAPORATOR PROBE TEST................ 8
EXPANSION VALVE....................... 7
HEATER PERFORMANCE TEST............. 8
LOW PRESSURE CUT-OFF SWITCH......... 11
SYSTEM CHARGE LEVEL TEST............ 11
VACUUM CONTROL SYSTEM.............. 12
SERVICE PROCEDURES
CHARGING A/C SYSTEM................. 14
EVACUATING REFRIGERANT SYSTEM....... 15R-134a REFRIGERANT................... 16
SERVICING REFRIGERANT OIL LEVEL...... 17
SYSTEM LEAK CHECKING................ 17
REMOVAL AND INSTALLATION
A/C FILTER/DRIER...................... 23
A/C SERVICE PORT VALVE CORES......... 18
BLOWER MOTOR AND WHEEL ASSEMBLY . . . 18
BLOWER MOTOR RESISTOR.............. 18
BLOWER MOTOR WHEEL................ 19
COMPRESSOR CLUTCH/COIL ASSEMBLY.... 19
COMPRESSOR......................... 19
CONDENSATION DRAIN TUBE............ 21
CONDENSER........................... 21
DISCHARGE LINE....................... 21
EVAPORATOR PROBE.................... 22
EVAPORATOR.......................... 21
EXPANSION VALVE...................... 23
HEATER CORE......................... 24
HEATER HOSES........................ 24
HIGH PRESSURE CUT OUT SWITCH........ 23
HIGH PRESSURE RELIEF VALVE........... 24
LIQUID LINE........................... 25
LOW PRESSURE CUT OFF SWITCH........ 25
MODE CONTROL CABLE................. 25
RECIRCULATION DOOR ACTUATOR........ 26
SUCTION LINE......................... 27
TEMPERATURE CONTROL CABLE.......... 27
UNIT HOUSING......................... 27
DISASSEMBLY AND ASSEMBLY
AIR DISTRIBUTION MODULE ±
RECONDITION........................ 28
ADJUSTMENTS
MODE CONTROL CABLE................. 30
TEMPERATURE CONTROL CABLE.......... 30
PLHEATING AND AIR CONDITIONING 24 - 1

COMPRESSOR
The compressor used on this vehicle is a Nippon-
denso 10PA17 R-134a. This compressor uses an alu-
minum swash plate, teflon coated pistons and
aluminum sleeved cylinder walls.
CAUTION: A 10PA17 R-12 compressor looks identi-
cal to a 10PA17 R-134a and will bolt up to the vehi-
cle. The 10PA17 R-12 compressor must not be used
on this system. It is extremely important that a
10PA17 R-134a compressor is identified prior to
using compressor in question. Check tag located
on compressor for model number.
NOISE
Excessive noise that occurs when the air condition-
ing is being used may be caused by:
²Loose bolts
²Mounting brackets
²Loose compressor clutch
²Excessive high refrigerant operating pressure
Verify the following before compressor repair is
performed:
(1) Compressor drive belt condition
(2) Proper refrigerant charge
(3) Thermal expansion valve (TXV) operating cor-
rectly
(4) Head pressure is normal
COMPRESSOR FRONT SHAFT SEAL
The compressor front shaft seal is not serviceable.
If a leak is detected at the shaft seal, the compressor
must be replaced as a unit.
CONDENSATION DRAIN TUBE
Condensation that accumulates in the evaporator
housing is drained from a tube through the dash and
on to the ground. This tube must be kept open to
prevent condensate water from collecting in the bot-
tom of the housing.
The tapered end of the drain tube is designed to
keep contaminants from entering the heater A/C unit
housing. If the tube is pinched or blocked, condensate
cannot drain, causing water to back up and spill into
the passenger compartment. It is normal to see con-
densate drainage below the vehicle. If the tube is
damaged, it should be replaced.
ENGINE COOLING SYSTEM REQUIREMENTS
To maintain ample temperature levels from the
heating-A/C system, the cooling system must be in
proper working order. Refer to Group 0, Lubrication
and Maintenance or Group 7, Cooling System of this
manual.
The use of a bug screen is not recommended. Any
obstructions forward of the condenser can reduce the
effectiveness of the air conditioning system.
EVAPORATOR PROBE
The evaporator probe can be replaced without hav-
ing to remove the unit housing from the vehicle.
The evaporator probe is located in the unit housing
and placed in the evaporator fins. The probe prevents
evaporator freeze-up. This is done by cycling the com-
pressor clutch OFF when evaporator temperature
drops below freeze point. It cycles ON when the
evaporator temperature rises above freeze point. The
evaporator probe uses a thermistor probe in a capil-
lary tube. The tube is inserted between the evapora-
tor fins in the heater-A/C unit housing.
HANDLING TUBING AND FITTINGS
Kinks in the refrigerant tubing or sharp bends in
the refrigerant hose lines will greatly reduce the
capacity of the entire system. High pressures are pro-
duced in the system when it is operating. Extreme
care must be exercised to make sure that all connec-
tions are pressure tight. Dirt and moisture can enter
the system when it is opened for repair or replace-
ment of lines or components. The refrigerant oil will
absorb moisture readily out of the air. This moisture
will convert into acids within a closed system.
Fig. 7 Resistor Block
24 - 4 HEATING AND AIR CONDITIONINGPL
DESCRIPTION AND OPERATION (Continued)

(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.
WARNING: PROTECT SKIN AND EYES FROM CON-
TACTING CO2 PERSONAL INJURY CAN RESULT.
(7) If suction side low pressure is within specified
range, freeze the expansion valve control head (Fig.
10) for 30 seconds. Use a super cold substance (liquid
CO2).Do not spray refrigerant on the expansion
valve for this test.Suction side low pressure should
drop to 34.5 kPa (5 psi) If not, replace expansion
valve.
(8) Allow expansion valve to thaw. The low pres-
sure gauge reading should stabilize at 103 to 241
kPa (15 to 35 psi). If not, replace expansion valve.
(9) When expansion valve test is complete, test
A/C overall performance. Refer to the Heater and A/C
Performance Test in this section. Remove all test
equipment before returning vehicle to use.
BLOWER MOTOR ELECTRICAL DIAGNOSIS
Refer to the Blower Motor Electrical System Diag-
nosis chart in this section. Also refer to Group 8W,
Wiring Diagrams for more information.
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.
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.
(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.
HEATER PERFORMANCE TEST
PRE-DIAGNOSTIC PREPARATIONS
Review Safety Precautions and Warnings in this
group before performing the following procedures.
Check the coolant level, drive belt tension, vacuum
line connections, radiator air flow and fan operation.
Start engine and allow to warm up to normal tem-
perature.
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 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
stabilizes, remove the cap completely.
24 - 8 HEATING AND AIR CONDITIONINGPL
DIAGNOSIS AND TESTING (Continued)

MAXIMUM HEATER OUTPUT: TEST AND
ACTION
Engine coolant is provided to the heater system by
two 16 mm (5/8 inch inside diameter) heater hoses.
With engine idling at normal running temperature,
set the control to maximum heat, floor, and high
blower setting. Using a test thermometer, check the
air temperature coming from the floor outlets, refer
to Temperature Reference Table.
If the floor outlet air temperature is insufficient,
refer to Group 7, Cooling Systems for specifications.
Both heater hoses should be HOT to the touch (cool-
ant return hose should be slightly cooler than the
supply hose). If coolant return hose is much cooler
than the supply hose, locate and repair engine cool-
ant flow obstruction in heater system.
POSSIBLE LOCATIONS OR CAUSE OF
OBSTRUCTED COOLANT FLOW
(1) Pinched or kinked heater hoses.
(2) Improper heater hose routing.
(3) Plugged heater hoses or supply and return
ports at cooling system connections, refer to Group 7,
Cooling System.(4) Plugged heater core.
(5) Air locked heater core.
(6) If coolant flow is verified and outlet tempera-
ture is insufficient, a mechanical problem may exist.
POSSIBLE LOCATION OR CAUSE OF
INSUFFICIENT HEAT
(1) Obstructed cowl air intake.
(2) Obstructed heater system outlets.
(3) Blend-air door not functioning properly.
TEMPERATURE CONTROL
If temperature cannot be adjusted with the TEMP
lever on the control panel, the following could require
service:
(1) Blend-air door binding.
(2) Faulty blend-air door cable.
(3) Improper engine coolant temperature.
(4) Faulty Instrument Panel Control.
LOW PRESSURE CUT-OFF SWITCH
The work area must not be below 21ÉC (70ÉF) 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 low pressure cut off
switch connector boot.
(3) Using a suitable jumper wire, jump across the
terminals inside wire connector boot.
(4) If the compressor clutch does not engage, the
cycling clutch switch, wiring, relay, or fuse can be
defective. Refer to Group 8W, Wiring Diagrams.
(5) If clutch engages, connect manifold gauge set.
Read low pressure gauge. At pressure above 97 kPa
(14 psi) and above, low pressure out off switch will
complete the clutch circuit. If the low pressure gauge
reads below 140 kPa (20 psi), the system is low on
refrigerant charge or empty due to a leak. Refer to
Service±Procedures, System Leak Checking in this
section.
(6) Install connector boot on switch and repeat
Step 3. If the clutch does not engage, replace the low
pressure cut off switch.
SYSTEM CHARGE LEVEL TEST
The procedure below should be used to check
and/or fill the refrigerant charge in the air condition-
ing system.
Fig. 11 Evaporator Probe Harness Connector
TEMPERATURE REFERENCE TABLE
Ambient Temp.Minimum
FloorOutlet
Temp.
Celsius Fahrenheit Celsius Fahrenheit
15.5É 60É 62.2É 144É
21.1É 70É 63.8É 147É
26.6É 80É 65.5É 150É
32.2É 90É 67.2É 153É
PLHEATING AND AIR CONDITIONING 24 - 11
DIAGNOSIS AND TESTING (Continued)