power DODGE RAM 2002 Service Repair Manual

(4) Remove seat dump handle.
(5) Pull shoulder belt out completely and clamp
shoulder belt to prevent shoulder belt from retracting
(Fig. 10).
(6) Remove shoulder belt anchor bolt.
(7) From the underside of the seat, remove the
inboard pivot bolt (Fig. 11).
WARNING: DO NOT REMOVE UPPER RECLINER
HANDLE, PULL ON UPPER RECLINER HANDLE OR
RECLINER CABLE END. THE RECLINER LEAD
SCREW IS SPRING LOADED AND WILL EJECT IF
EITHER THE HANDLE OR CABLE IS PULLED
BEFORE THE LEAD SCREW IS REMOVED.
(8) Remove clip attaching recliner cable (Fig. 12)
to seat track adjuster and separate the cable from
the seat track adjuster.
(9) Remove the inboard and outboard pivot bolts
attaching the frame to the seat track adjuster (Fig.
13).
(10) Remove recliner lower bolt.
(11) Separate seat back from seat track adjuster.
INSTALLATION
STANDARD CAB
(1) Align seat cushion with seat back and install
shoulder bolt through seat back into seat cushion
frame on inboard side. Tighten bolt to 49 N´m (36 ft.
lbs.) torque.
(2) Install bolts through seat back latch into seat
cushion frame. Tighten bolts to 25 N´m (18 ft. lbs.)
torque.
(3) Connect rear end flap J-Straps and pull rear
J-Strap up and secure to frame.(4) Install seat in vehicle.
(5) Connect power seat switch connector, if
equipped.
Fig. 10 Shoulder Belt Clamp
1 - CLAMP
2 - SEAT BACK
3 - SHOULDER BELT
Fig. 11 Pivot Bolt
1 - SEAT BACK FRAME
2 - RECLINER
3 - SEAT TRACK ADJUSTER
4 - RISER
5 - SEAT CUSHION FRAME
Fig. 12 Recliner Cable
1 - POWER SEAT SWITCH
2 - PIVOT BOLT
3 - RECLINER CABLE
4 - LOWER RECLINER BOLT
5 - SEAT TRACK
6 - SEAT RISER
7 - SEAT TRACK ADJUSTER
23 - 136 SEATSBR/BE
SEAT BACK - SPLIT BENCH (Continued)

SEAT TRACK - SPLIT BENCH
REMOVAL
(1) Remove seat from vehicle. (Refer to 23 -
BODY/SEATS/SEAT - SPLIT BENCH - REMOVAL)
(2) Remove bolts from crossbrace to seat cushion
frame and power track (Fig. 24).
(3) Remove bolts attaching center seat to seat
frame and remove center seat.
(4) Remove bolts attaching seat track to seat
frame (Fig. 25) and (Fig. 26).
INSTALLATION
(1) Install bolts attaching seat track to seat frame.
Tighten bolts to 25 N´m (18 ft. lbs.) torque.
(2) Install bolts into crossbrace and seat cushion
frame to power track and torque to 10 N´m (8.5±11.5
ft. lbs.).
(3) Install bolts attaching center seat to seat
frame. Tighten bolts to 25 N´m (18 ft. lbs.) torque.
(4) Install seat. (Refer to 23 - BODY/SEATS/SEAT
- SPLIT BENCH - INSTALLATION)
(5) Power adjuster on power seat must be cycled in
all 6 functions to ensure the adjuster is working
properly.
Fig. 24 Cross Brace
1 - CROSS BRACE
2 - SEAT TRACK
Fig. 25 Power Seat Track
1 - SEAT SWITCH
Fig. 26 Seat Track Removal/Installation
1 - RELEASE HANDLE
2 - SEAT TRACK
23 - 142 SEATSBR/BE

A/C Diagnosis
Condition Possible Causes Correction
2. Faulty a/c low
pressure switch.2. (Refer to Controls/A/C Low Pressure Switch/Diagnosis
and Testing) in this group. Test the a/c low pressure
switch and replace, if required.
3. Faulty Powertrain
Control Module (PCM).3. (Refer to Appropriate Diagnostic Information) for testing
the PCM. Test the PCM and replace, if required.
EQUAL PRESSURES,
BUT THE
COMPRESSOR CLUTCH
DOES NOT ENGAGE.1. No refrigerant in the
refrigerant system.1. (Refer to Plumbing/Diagnosis and Testing - Refrigerant
System Leaks) in this group. Test the refrigerant system
for leaks. Repair, evacuate and charge the refrigerant
system, if required.
2. Faulty fuse. 2. Check the fuses in the Power Distribution Center and
the junction block. Repair the shorted circuit or
component and replace the fuses, if required.
3. Faulty a/c compressor
clutch coil.3. (Refer to Controls/A/C Compressor Clutch Coil/
Diagnosis and Testing) in this group. Test the compressor
clutch coil and replace, if required.
4. Faulty a/c compressor
clutch relay.4. (Refer to Controls/A/C Compressor Clutch Relay/
Diagnosis and Testing) in this group. Test the compressor
clutch relay and relay circuits. Repair the circuits or
replace the relay, if required.
5. Improperly installed or
faulty a/c low pressure
switch.5. (Refer to Controls/A/C Low Pressure Switch/Diagnosis
and Testing) in this group. Test the a/c low pressure
switch and tighten or replace, if required.
6. Faulty a/c high
pressure switch.6. (Refer to Controls/A/C High Pressure Switch/Diagnosis
and Testing) in this group. Test the a/c high pressure
switch and replace, if required.
7. Faulty Powertrain
Control Module (PCM).7. (Refer to Appropriate Diagnostic Information) for testing
the PCM. Test the PCM and replace, if required.
8. Faulty a/c heater
control.8. (Refer to Controls/A/C Heater Control/Diagnosis and
Testing) in this group. Test the a/c heater control and
replace, if required.
NORMAL PRESSURES,
BUT A/C
PERFORMANCE TEST
AIR TEMPERATURES AT
CENTER PANEL
OUTLET ARE TOO
HIGH.1. Excessive refrigerant
oil in system.1. (Refer to Plumbing/Refrigerant Oil/Standard Procedure
- Refrigerant Oil Level) in this group. Recover the
refrigerant from the refrigerant system and inspect the
refrigerant oil content. Restore the refrigerant oil to the
proper level, if required.
2. Blend door actuator
inoperative or faulty.2. Check the Blend Door Actuator operation. Replace as
required.
3. Blend door
inoperative, obstructed or
sealing improperly.3. (Refer to Distribution/Blend Door/Removal/Installation)
in this group. Inspect the blend door for proper operation
and sealing and correct, if required.
LOW SIDE PRESSURE
IS NORMAL OR
SLIGHTLY LOW, AND
HIGH SIDE PRESSURE
IS TOO LOW.1. Low refrigerant system
charge.1. (Refer to Plumbing/Diagnosis and Testing - Refrigerant
System Leaks) in this group. Test the refrigerant system
for leaks. Repair, evacuate and charge the refrigerant
system, if required.
24 - 4 HEATING & AIR CONDITIONINGBR/BE
HEATING & AIR CONDITIONING (Continued)

OPERATION
The compressor clutch assembly provides the
means to engage and disengage the compressor from
the engine serpentine accessory drive belt. When the
clutch coil is energized, it magnetically draws the
clutch into contact with the pulley and drives the
compressor shaft. When the coil is not energized, the
pulley freewheels on the clutch hub bearing, which is
part of the pulley. The compressor clutch and coil are
the only serviced parts on the compressor.
The compressor clutch engagement is controlled by
several components: the a/c heater mode control
switch, the a/c loss of charge switch, the a/c pressure
transducer, the compressor clutch relay, the evapora-
tor temperature sensor and the Powertrain Control
Module (PCM). The PCM may delay compressor
clutch engagement for up to thirty seconds(Refer to 8
- ELECTRICAL/ELECTRONIC CONTROL MOD-
ULES/POWERTRAIN CONTROL MODULE -
DESCRIPTION).
DIAGNOSIS AND TESTING - A/C COMPRESSOR
CLUTCH COIL
For circuit descriptions and diagrams, (Refer to
Appropriate Wiring Information). The battery must
be fully-charged before performing the following
tests. Refer to Battery for more information.
(1) Connect an ammeter (0 to 10 ampere scale) in
series with the clutch coil terminal. Use a voltmeter
(0 to 20 volt scale) with clip-type leads for measuring
the voltage across the battery and the compressor
clutch coil.(2) With the a/c heater mode control switch in any
A/C mode, and the blower motor switch in the lowest
speed position, start the engine and run it at normal
idle.
(3) The compressor clutch coil voltage should read
within 0.2 volts of the battery voltage. If there is
voltage at the clutch coil, but the reading is not
within 0.2 volts of the battery voltage, test the clutch
coil feed circuit for excessive voltage drop and repair
as required. If there is no voltage reading at the
clutch coil, use a DRB IIItscan tool and (Refer to
Appropriate Diagnostic Information) for testing of the
compressor clutch circuit. The following components
must be checked and repaired as required before you
can complete testing of the clutch coil:
²Fuses in the junction block and the Power Dis-
tribution Center (PDC)
²A/C Heater mode control switch
²Compressor clutch relay
²A/C High Pressure Switch
²A/C Low Pressure Switch
²Powertrain Control Module (PCM).
(4) The compressor clutch coil is acceptable if the
current draw measured at the clutch coil is 2.0 to 3.9
amperes with the electrical system voltage at 11.5 to
12.5 volts. This should only be checked with the work
area temperature at 21É C (70É F). If system voltage
is more than 12.5 volts, add electrical loads by turn-
ing on electrical accessories until the system voltage
drops below 12.5 volts.
(a) If the clutch coil current reading is four
amperes or more, the coil is shorted and should be
replaced.
(b) If the clutch coil current reading is zero, the
coil is open and should be replaced.
STANDARD PROCEDURE - A/C COMPRESSOR
CLUTCH BREAK-IN
After a new compressor clutch has been installed,
cycle the compressor clutch approximately twenty
times (five seconds on, then five seconds off). During
this procedure, set the A/C Heater control to the
Recirculation Mode, the blower motor switch in the
highest speed position, and the engine speed at 1500
to 2000 rpm. This procedure (burnishing) will seat
the opposing friction surfaces and provide a higher
compressor clutch torque capability.
REMOVAL
The refrigerant system can remain fully-charged
during compressor clutch, pulley, or coil replacement.
The compressor clutch can be serviced in the vehicle.
(1) Disconnect and isolate the battery negative
cable.
(2) On models with the diesel engine option,
remove the compressor from the engine. Do not
Fig. 4 COMPRESSOR CLUTCH - TYPICAL
1 - CLUTCH PLATE
2 - SHAFT KEY
3 - PULLEY
4 - COIL
5 - CLUTCH SHIMS
6 - SNAP RING
7 - SNAP RING
BR/BECONTROLS 24 - 13
A/C COMPRESSOR CLUTCH (Continued)

NOTE: The air gap is determined by the spacer
shims. When installing an original, or a new clutch
assembly, try the original shims first. When install-
ing a new clutch onto a compressor that previously
did not have a clutch, use 1.0, 0.50, and 0.13 milli-
meter (0.040, 0.020, and 0.005 inch) shims from the
clutch hardware package that is provided with the
new clutch.
(12) On models with the diesel engine option,
install the compressor on the engine. (Refer to 24 -
HEATING & AIR CONDITIONING/PLUMBING/A/C
COMPRESSOR - INSTALLATION)
(13) Connect the battery negative cable.
A/C COMPRESSOR CLUTCH
RELAY
DESCRIPTION
The a/c compressor clutch relay is a International
Standards Organization (ISO) micro-relay. The termi-
nal designations and functions are the same as a con-
ventional ISO relay. However, the micro-relay
terminal orientation (footprint) is different, the cur-
rent capacity is lower, and the relay case dimensions
are smaller than those of the conventional ISO relay.
OPERATION
The compressor clutch relay is a electromechanical
device that switches battery current to the compres-
sor clutch coil when the Powertrain Control Module
(PCM) grounds the coil side of the relay. The PCM
responds to inputs from the a/c heater control, the a/closs of charge switch, the a/c pressure transducer and
the evaporator fin probe.
The compressor clutch relay is located in the Power
Distribution Center (PDC) in the engine compart-
ment. Refer to the PDC label for relay identification
and location.
The compressor clutch relay cannot be repaired
and, if faulty or damaged, it must be replaced.
DIAGNOSIS AND TESTING - A/C COMPRESSOR
CLUTCH RELAY
RELAY TEST
The compressor clutch relay (Fig. 16) is located in
the Power Distribution Center (PDC). Refer to the
PDC label for relay identification and location.
Remove the relay from the PDC to perform the fol-
lowing tests:
(1) A relay in the de-energized position should
have continuity between terminals 87A and 30, and
no continuity between terminals 87 and 30. If OK, go
to Step 2. If not OK, replace the faulty relay.
(2) Resistance between terminals 85 and 86 (elec-
tromagnet) should be 75   5 ohms. If OK, go to Step
3. If not OK, replace the faulty relay.
(3) Connect a battery to terminals 85 and 86.
There should now be continuity between terminals
30 and 87, and no continuity between terminals 87A
and 30. If OK, see the Relay Circuit Test below. If not
OK, replace the faulty relay.
RELAY CIRCUIT TEST
For circuit descriptions and diagrams, (Refer to
Appropriate Wiring Information).
Fig. 15 CHECK CLUTCH AIR GAP
1 - FEELER GAUGE
Fig. 16 COMPRESSOR CLUTCH RELAY
TERMINAL LEGEND
NUMBER IDENTIFICATION
30 COMMON FEED
85 COIL GROUND
86 COIL BATTERY
87 NORMALLY OPEN
87A NORMALLY CLOSED
BR/BECONTROLS 24 - 17
A/C COMPRESSOR CLUTCH (Continued)

(1) The relay common feed terminal cavity (30) is
connected to fused battery feed. There should be bat-
tery voltage at the cavity for relay terminal 30 at all
times. If OK, go to Step 2. If not OK, repair the open
circuit to the fuse in the PDC as required.
(2) The relay normally closed terminal (87A) is not
used in this application. Go to Step 3.
(3) The relay normally open terminal cavity (87) is
connected to the compressor clutch coil. There should
be continuity between this cavity and the A/C com-
pressor clutch relay output circuit cavity of the com-
pressor clutch coil wire harness connector. If OK, go
to Step 4. If not OK, repair the open circuit as
required.
(4) The relay coil battery terminal (86) is con-
nected to the fused ignition switch output (run/start)
circuit. There should be battery voltage at the cavity
for relay terminal 86 with the ignition switch in the
On position. If OK, go to Step 5. If not OK, repair the
open circuit to the fuse in the junction block as
required.
(5) The coil ground terminal cavity (85) is switched
to ground through the Powertrain Control Module
(PCM). There should be continuity between this cav-
ity and the A/C compressor clutch relay control cir-
cuit cavity of the PCM wire harness connector C
(gray) at all times. If not OK, repair the open circuit
as required.
REMOVAL
(1) Disconnect and isolate the battery negative
cable.
(2) Remove the cover from the Power Distribution
Center (PDC) (Fig. 17).
(3) Refer to the label on the PDC for compressor
clutch relay identification and location.(4) Unplug the compressor clutch relay from the
PDC and remove it.
INSTALLATION
(1) Install the compressor clutch relay by aligning
the relay terminals with the cavities in the PDC and
pushing the relay firmly into place.
(2) Install the PDC cover.
(3) Connect the battery negative cable.
(4) Test the relay operation.
A/C-HEATER CONTROL
DESCRIPTION
Both the heater-only and a/c heater systems use a
combination of electrical and vacuum controls. These
controls provide the vehicle operator with a number
of setting options to help control the climate and
comfort within the vehicle. Refer to the owner's man-
ual in the vehicle glove box for more information on
the features, use, and suggested operation of these
controls.
OPERATION
The heater-only or a/c heater control panel is
located to the right of the instrument cluster on the
instrument panel. The control panel contains a rota-
ry-type temperature control knob, a rotary-type mode
control switch knob, and a rotary-type blower motor
speed switch knob. On models with the optional
heated mirror system, a momentary push button
switch and indicator lamp are located near the bot-
tom of the a/c heater control panel. Refer to Heated
Mirrors for more information on this feature.
The heater-only or a/c heater control panel cannot
be repaired. If faulty or damaged, the entire unit
must be replaced. The control knobs and the illumi-
nation lamps are available for service replacement.
DIAGNOSIS AND TESTING - A/C HEATER
CONTROL
Satisfactory heater and air conditioner perfor-
mance depends upon proper operation and adjust-
ment of all operating controls and refrigeration
system components. For circuit descriptions and dia-
grams, (Refer to Appropriate Wiring Information).
These inspections, tests, and adjustments should be
used to locate the cause of a malfunction.
Operation must be tested as described in the fol-
lowing sequence:
(1) Inspect and adjust the serpentine drive bel-
t(Refer to 7 - COOLING/ACCESSORY DRIVE/DRIVE
BELTS - DIAGNOSIS AND TESTING).
(2) Start the engine and hold the idle speed at
1,300 rpm.
Fig. 17 POWER DISTRIBUTION CENTER
1 - COVER
2 - POWER DISTRIBUTION CENTER
24 - 18 CONTROLSBR/BE
A/C COMPRESSOR CLUTCH RELAY (Continued)

(4) Reinstall the cluster bezel to the instrument
panel(Refer to 23 - BODY/INSTRUMENT PANEL/
CLUSTER BEZEL - INSTALLATION).
(5) Reach under the instrument panel to reinstall
the a/c heater control vacuum harness retainer to the
side of the center distribution duct.
(6) Plug in the two halves of the a/c heater control
to HVAC housing vacuum harness connector.
(7) Connect the battery negative cable.
A/C HIGH PRESSURE SWITCH
DESCRIPTION
The a/c high pressure switch is located on the dis-
charge line near the compressor. The switch is
screwed onto a fitting that contains a Schrader-type
valve, which allows the switch to be serviced without
discharging the refrigerant system. The discharge
line fitting is equipped with an O-ring to seal the
switch connection.
OPERATION
The a/c high pressure switch is connected in series
electrically with the a/c low pressure switch between
ground and the Powertrain Control Module (PCM).
The switch contacts open and close causing the PCM
to turn the compressor clutch on and off. This pre-
vents compressor operation when the discharge line
pressure approaches high levels.
The a/c high pressure switch contacts are open
when the discharge line pressure rises above about3100 to 3375 kPa (450 to 490 psi). The switch con-
tacts will close when the discharge line pressure
drops to about 1860 to 2275 kPa (270 to 330 psi).
When checking refrigerant system pressures with a
manifold gauge set, keep in mind that the indicated
pressures will be about 172 kpa (25 psi) below the
actual switch pressure values due to the pressure
drop that occurs in the refrigerant system between
the switch and the high pressure service port.
The a/c high pressure switch is a factory-calibrated
unit. The switch cannot be adjusted or repaired and,
if faulty or damaged, it must be replaced.
DIAGNOSIS AND TESTING - A/C HIGH
PRESSURE SWITCH
Before performing diagnosis of the a/c high pres-
sure switch, verify that the refrigerant system has
the correct refrigerant charge. (Refer to 24 - HEAT-
ING & AIR CONDITIONING - DIAGNOSIS AND
TESTING)
For circuit descriptions and diagrams, (Refer to
Appropriate Wiring Information).
(1) Disconnect and isolate the battery negative
cable.
(2) Unplug the a/c high pressure switch wire har-
ness connector from the switch on the refrigerant
system fitting.
(3) On the four terminal high pressure switch,
check for continuity between terminals C and D. On
the two terminal switch, check for continuity
between both terminals of the a/c high pressure
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.
REMOVAL
(1) Disconnect and isolate the battery negative
cable.
(2) Unplug the wire harness connector from the a/c
high pressure switch, which is mounted to a fitting
on the discharge line between the compressor and
the condenser inlet.
(3) Unscrew the a/c high pressure switch from the
discharge line fitting.
(4) Remove the a/c high pressure switch from the
vehicle.
(5) Remove the O-ring seal from the discharge line
fitting and discard.
INSTALLATION
(1) Lubricate a new O-ring seal with clean refrig-
erant oil and install it on the discharge line fitting.
Use only the specified O-rings as they are made of a
special material for the R-134a system. Use only
refrigerant oil of the type recommended for the com-
pressor in the vehicle. (Refer to 24 - HEATING &
Fig. 19 A/C HEATER CONTROL REMOVE/INSTALL
1 - HEATED MIRROR WIRE HARNESS CONNECTOR
2 - WIRE HARNESS CONNECTOR
3 - SCREW
4 - HEATER-A/C CONTROL
24 - 20 CONTROLSBR/BE
A/C-HEATER CONTROL (Continued)

AIR CONDITIONING/PLUMBING/REFRIGERANT
OIL - DESCRIPTION)
(2) Install and tighten the high pressure cut-off
switch on the discharge line fitting. The switch
should be hand-tightened onto the discharge line fit-
ting.
(3) Plug the wire harness connector into the high
pressure cut-off switch.
(4) Connect the battery negative cable.
A/C LOW PRESSURE SWITCH
DESCRIPTION
The a/c low pressure switch is located on the top of
the accumulator. The switch is screwed onto an accu-
mulator fitting that contains a Schrader-type valve,
which allows the switch to be serviced without dis-
charging the refrigerant system. The accumulator fit-
ting is equipped with an O-ring to seal the switch
connection.
OPERATION
The a/c low pressure switch is connected in series
electrically with the a/c high pressure switch and the
a/c heater control, between ground and the Power-
train Control Module (PCM). The switch contacts
open and close causing the PCM to turn the compres-
sor clutch on and off. This regulates the refrigerant
system pressure and controls evaporator tempera-
ture. Controlling evaporator temperature prevents
condensate water on the evaporator fins from freez-
ing and obstructing air conditioning system air flow.
The a/c low pressure switch contacts are open
when the suction pressure is about 152-165 kPa
(22-24 psi) or lower. The switch contacts will close
when the suction pressure rises to about 255-296 kPa
(37-43 psi) or above. Lower ambient temperatures,
below about -1É C (30É F), will also cause the switch
contacts to open. This is due to the pressure/temper-
ature relationship of the refrigerant in the system.
The a/c low pressure switch is a factory-calibrated
unit. It cannot be adjusted or repaired and, if faulty
or damaged, it must be replaced.
DIAGNOSIS AND TESTING - A/C LOW
PRESSURE SWITCH
Before performing diagnosis of the a/c low pressure
switch, be certain that the switch is properly
installed on the accumulator fitting. If the switch is
too loose it may not open the Schrader-type valve in
the accumulator fitting, which will prevent the
switch from correctly monitoring the refrigerant sys-
tem pressure. Also verify that the refrigerant system
has the correct refrigerant charge. (Refer to 24 -HEATING & AIR CONDITIONING - DIAGNOSIS
AND TESTING - A/C PERFORMANCE)
Remember that lower ambient temperatures, below
about -1É C (30É F), during cold weather will open the
switch contacts and prevent compressor operation
due to the pressure/temperature relationship of the
refrigerant. For circuit descriptions and diagrams,
(Refer to Appropriate Wiring Information).
(1) Disconnect and isolate the battery negative
cable.
(2) Unplug the a/c low pressure switch wire har-
ness connector from the switch on the accumulator
fitting.
(3) Install a jumper wire between the two cavities
of the a/c low pressure switch wire harness connector.
(4) Connect a manifold gauge set to the refrigerant
system service ports. (Refer to 24 - HEATING & AIR
CONDITIONING/PLUMBING - STANDARD PRO-
CEDURE - REFRIGERANT SYSTEM SERVICE
EQUIPMENT)
(5) Connect the battery negative cable.
(6) Place the a/c heater mode control switch knob
in any A/C position and start the engine.
(7) Check for continuity between the two terminals
of the low pressure cycling clutch switch. There
should be continuity with a suction pressure reading
of 296 kPa (43 psi) or above, and no continuity with a
suction pressure reading of 172 kPa (25 psi) or below.
If OK, test and repair the A/C switch sense circuit as
required. If not OK, replace the faulty switch.
REMOVAL
(1) Disconnect and isolate the battery negative
cable.
(2) Unplug the wire harness connector from the a/c
low pressure switch on the top of the accumulator
(Fig. 20).
(3) Unscrew the a/c low pressure switch from the
fitting on the top of the accumulator.
(4) Remove the O-ring seal from the accumulator
fitting and discard.
INSTALLATION
(1) Lubricate a new O-ring seal with clean refrig-
erant oil and install it on the accumulator fitting.
Use only the specified O-rings as they are made of a
special material for the R-134a system. Use only
refrigerant oil of the type recommended for the com-
pressor in the vehicle. (Refer to 24 - HEATING &
AIR CONDITIONING/PLUMBING/REFRIGERANT
OIL - DESCRIPTION)
(2) Install and tighten the a/c low pressure switch
on the accumulator fitting. The switch should be
hand-tightened onto the accumulator fitting.
(3) Plug the wire harness connector into the a/c
low pressure switch.
BR/BECONTROLS 24 - 21
A/C HIGH PRESSURE SWITCH (Continued)

(4) Connect the battery negative cable.
BLOWER MOTOR RELAY
DESCRIPTION
The blower motor relay is an International Stan-
dards Organization (ISO)-type relay. The relay is an
electromechanical device that switches battery cur-
rent from a fuse in the Power Distribution Center
(PDC) directly to the blower motor. The relay is ener-
gized when the relay coil is provided a voltage signal
by the ignition switch. This arrangement reduces the
amount of battery current that must flow through
the ignition switch.
OPERATION
The blower motor relay control circuit is protected
by a fuse located in the junction block. When the
relay is de-energized, the blower motor receives no
battery current.The blower motor relay is located in the PDC in
the engine compartment. Refer to the PDC label for
blower motor relay identification and location.
The blower motor relay cannot be repaired and, if
faulty or damaged, it must be replaced.
DIAGNOSIS AND TESTING - BLOWER MOTOR
RELAY
RELAY TEST
The blower motor relay (Fig. 21) is located in the
Power Distribution Center (PDC). Remove the blower
motor relay from the PDC to perform the following
tests:
(1) A relay in the de-energized position should
have continuity between terminals 87A and 30, and
no continuity between terminals 87 and 30. If OK, go
to Step 2. If not OK, replace the faulty relay.
(2) Resistance between terminals 85 and 86 (elec-
tromagnet) should be 75   5 ohms. If OK, go to Step
3. If not OK, replace the faulty relay.
(3) Connect a battery to terminals 85 and 86.
There should now be continuity between terminals
30 and 87, and no continuity between terminals 87A
and 30. If OK, see Relay Circuit Test below. If not
OK, replace the faulty relay.
RELAY CIRCUIT TEST
For circuit descriptions and diagrams, (Refer to
Appropriate Wiring Information).
Fig. 20 ACCUMULATOR AND A/C LOW PRESSURE
SWITCH
1 - CLIP
2 - BRACKET
3 - SCREW
4 - BAND
5 - ACCUMULATOR
6 - TO SUCTION LINE
7 - A/C LOW PRESSURE SWITCH
8 - FROM EVAPORATOR OUTLET
Fig. 21 BLOWER MOTOR RELAY
TERMINAL LEGEND
NUMBER IDENTIFICATION
30 COMMON FEED
85 COIL GROUND
86 COIL BATTERY
87 NORMALLY OPEN
87A NORMALLY CLOSED
24 - 22 CONTROLSBR/BE
A/C LOW PRESSURE SWITCH (Continued)

(1) The relay common feed terminal cavity (30) is
connected to fused battery feed directly from a fuse
in the Power Distribution Center (PDC), and should
be hot at all times. Check for battery voltage at the
PDC cavity for relay terminal 30. If OK, go to Step 2.
If not OK, repair the open circuit to the PDC fuse as
required.
(2) The relay normally closed terminal cavity (87A)
is not used for this application. Go to Step 3.
(3) The relay normally open terminal cavity (87) is
connected to the blower motor. When the relay is
energized, terminal 87 is connected to terminal 30
and provides full battery current to the blower motor
feed circuit. There should be continuity between the
PDC cavity for terminal 87 and the blower motor
relay output circuit cavity of the blower motor wire
harness connector at all times. If OK, go to Step 4. If
not OK, repair the open circuit to the blower motor
as required.
(4) The coil battery terminal cavity (86) is con-
nected to the ignition switch. When the ignition
switch is placed in the On position, fused ignition
switch output is directed from a fuse in the junction
block to the relay electromagnetic coil to energize the
relay. There should be battery voltage at the PDC
cavity for relay terminal 86 with the ignition switch
in the On position. If OK, go to Step 5. If not OK,
repair the open circuit to the junction block fuse as
required.
(5) The coil ground terminal cavity (85) is con-
nected to ground. This terminal supplies the ground
for the relay electromagnetic coil. There should be
continuity between the PDC cavity for relay terminal
85 and a good ground at all times. If not OK, repair
the open circuit as required.
REMOVAL
(1) Disconnect and isolate the battery negative
cable.
(2) Remove the cover from the Power Distribution
Center (PDC) (Fig. 22).
(3) Refer to the label on the PDC for blower motor
relay identification and location.
(4) Unplug the blower motor relay from the PDC
and remove it.
INSTALLATION
(1) Install the blower motor relay by aligning the
relay terminals with the cavities in the PDC and
pushing the relay firmly into place.
(2) Install the PDC cover.
(3) Connect the battery negative cable.
(4) Test the relay operation.
BLOWER MOTOR RESISTOR
BLOCK
DESCRIPTION
The blower motor resistor is mounted to the bot-
tom of the HVAC housing, under the instrument
panel and just inboard of the blower motor. It can be
accessed without removing any other components.
OPERATION
The resistor has multiple resistor wires, each of
which will change the resistance in the blower motor
ground path to change the blower motor speed. The
blower motor switch directs the ground path through
the correct resistor wire to obtain the selected blower
motor speed.
With the blower motor switch in the lowest speed
position, the ground path for the motor is applied
through all of the resistor wires. Each higher speed
selected with the blower motor switch applies the
blower motor ground path through fewer of the resis-
tor wires, increasing the blower motor speed. When
the blower motor switch is in the highest speed posi-
tion, the blower motor resistor is bypassed and the
blower motor receives a direct path to ground.
The blower motor resistor cannot be repaired and,
if faulty or damaged, it must be replaced.
DIAGNOSIS AND TESTING - BLOWER MOTOR
RESISTOR BLOCK
For circuit descriptions and diagrams, (Refer to
Appropriate Wiring Information).
Fig. 22 POWER DISTRIBUTION CENTER
1 - COVER
2 - POWER DISTRIBUTION CENTER
BR/BECONTROLS 24 - 23
BLOWER MOTOR RELAY (Continued)