relay DODGE RAM 2001 Service Repair Manual

The governor plug serves a dual purpose:
²It allows the shift valves to move either left or
right, allowing both upshifts and downshifts.
²When in a manual selection position, it will be
hydraulically ªblockedº into position so no upshift can
occur.
The physical blocking of the upshift while in the
manual ª1º position is accomplished by the directing
of line pressure between both lands of the governor
plug. The line pressure reacts against the larger land
of the plug, pushing the plug back against the end
plate overcoming governor pressure. With the combi-
nation of the line pressure and spring pressure, the
valve cannot move, preventing any upshift.
1-2 SHIFT CONTROL VALVE
It contains a valve with four lands and a spring. It
is used as both a ªrelayº and ªbalancedº valve.
The valve has two specific operations (Fig. 252):
²Aid in quality of the 1-2 upshift.
²Aid in the quality and timing of the 3-2 kick-
down ranges.
When the manual valve is set to the DRIVE posi-
tion and the transmission is in the first or second
gear range, 1-2 shift control or ªmodulated throttle
pressureº is supplied to the middle of the accumula-
tor piston by the 1-2 shift control valve. During the
1-2 upshift, this pressure is used to control the kick-
down servo apply pressure that is needed to apply
the kickdown and accumulator pistons. Thus, the 1-2
shift point is ªcushionedº and the quality is
improved. During a WOT kickdown, kickdown pres-
sure is applied between the kickdown valve and the
1-2 shift control valve. This additional pressure is
directed to the 1-2 shift control's spring cavity, add-
ing to the spring load on the valve. The result of this
increased ªmodulatedº throttle pressure is a firmer
WOT upshift.
2-3 SHIFT VALVE
The 2-3 shift valve mechanism (Fig. 253) consists
of the 2-3 shift valve, governor plug and spring, and
a throttle plug. After the 1-2 shift valve has com-
pleted its operation and applied the front band, line
pressure is directed to the 2-3 shift valve through the
connecting passages from the 1-2 shift valve. The line
pressure will then dead±end at land #2 until the 2-3
valve is ready to make its shift. Now that the vehicle
is in motion and under acceleration, there is throttle
pressure being applied to the spring side of the valve
and between lands #3 and #4.
As vehicle speed increases, governor pressure
increases proportionately, until it becomes great
enough to overcome the combined throttle and spring
pressure on the right side of the valve. Since the
throttle pressure end of the 2-3 shift valve is larger
in diameter than the 1-2 shift valve, the 2-3 shift will
always happen at a greater speed than the 1-2 shift.
When this happens, the governor plug is forced
against the shift valve moving it to the right. The
shift valve causes land #4 to close the passage sup-
plying throttle pressure to the 2-3 shift valve. With-
out throttle pressure present in the circuit now, the
governor plug will push the valve over far enough to
bottom the valve in its bore. This allows land #2 to
direct line pressure to the front clutch.
Fig. 251 1-2 Shift Valve-After Shift
21 - 790 AUTOMATIC TRANSMISSION - 47REBR/BE
VALVE BODY (Continued)

back up to the switch valve. From the switch valve,
the fluid pressure is directed to the transmission
cooler, and lubrication pressure returns from the
cooler to lubricate different portions of the transmis-
sion.
Once the TCC control valve has moved to the right
(Fig. 259), line pressure is directed to the tip of the
switch valve, forcing the valve to the right. The
switch valve now vents oil from the front of the pis-
ton in the torque converter, and supplies line pres-
sure to the (rear) apply side of the torque converter
piston. This pressure differential causes the piston toapply against the friction material, cutting off any
further flow of line pressure oil. After the switch
valve is shuttled right allowing line pressure to
engage the TCC, torque converter pressure is
directed past the switch valve into the transmission
cooler and lubrication circuits.
MANUAL VALVE
The manual valve (Fig. 260) is a relay valve. The
purpose of the manual valve is to direct fluid to the
correct circuit needed for a specific gear or driving
range. The manual valve, as the name implies, is
Fig. 258 Switch Valve-Torque Converter Unlocked
BR/BEAUTOMATIC TRANSMISSION - 47RE 21 - 795
VALVE BODY (Continued)

hook formations on the lower edge of the glove box
door are engaged with and pivot on three hinge pins
integral to the lower edge of the instrument panel
support structure. The glove box door also serves as
the passenger side knee blocker. A honeycomb struc-
ture between the inner and outer glove box door pan-
els helps to absorb the impact load and distribute it
to the instrument panel structure.
²Steering Column Opening Cover- The steer-
ing column opening cover serves as the driver side
knee blocker. This molded plastic cover has an inte-
gral ribbed plastic liner concealed behind it, for
increased strength and integrity. The steering column
opening cover transfers impact loads to the instru-
ment panel structural support.
²Top Cover- The instrument panel top cover or
base trim is the molded, grained, and color impreg-
nated plastic outer skin of the instrument panel
structural support.
Hard wired circuitry connects the electrical compo-
nents on the instrument panel to each other through
the electrical system of the vehicle. These hard wired
circuits are integral to several wire harnesses, which
are routed throughout the vehicle and retained by
many different methods. These circuits may be con-
nected to each other, to the vehicle electrical system
and to the instrument panel components through the
use of a combination of soldered splices, splice block
connectors and many different types of wire harness
terminal connectors and insulators. Refer to the
appropriate wiring information. The wiring informa-
tion includes complete circuit diagrams, proper wire
and connector repair procedures, further details on
wire harness routing and retention, as well as pin-
out and location views for the various wire harness
connectors, splices, and grounds.
OPERATION
The instrument panel serves as the command cen-
ter of the vehicle, which necessarily makes it a very
complex unit. The instrument panel is designed to
house the controls and monitors for standard and
optional powertrains, climate control systems, audio
systems, safety systems, and many other comfort or
convenience items. When the components of the
instrument panel structural support are properly
assembled and secured in the vehicle they provide
superior instrument panel stiffness and integrity to
help reduce buzzes, squeaks, and rattles. This type of
construction also provides improved energy absorp-
tion which, in conjunction with the dual airbags and
seat belts, helps to improve occupant protection.
The instrument panel is also designed so that all of
the various controls can be safely reached and the
monitors can be easily viewed by the vehicle operator
when driving, while still allowing relative ease ofaccess to each of these items for service. Modular
instrument panel construction allows all of the
gauges and controls to be serviced from the front of
the panel. In addition, most of the instrument panel
electrical components can be accessed without com-
plete instrument panel removal. However, if neces-
sary, the instrument panel can be removed from the
vehicle as an assembly.
The steering column opening cover with its inte-
gral knee blocker located on the driver side of the
instrument panel works in conjunction with the air-
bag system in a frontal vehicle impact to keep the
driver properly positioned for an airbag deployment.
In addition, removal of this component provides
access to the steering column mounts, the steering
column wiring, the Junction Block (JB) (removal of a
snap-fit fuse access panel on the left end of the
instrument panel allows access to the fuses and cir-
cuit breakers), the Central Timer Module (CTM), the
Infinity speaker filter choke and relay unit, much of
the instrument panel wiring, and the gear selector
indicator cable (automatic transmission).
In a frontal collision, the glove box door on the pas-
senger side of the instrument panel provides the
same function for the front seat passenger as the
knee blocker does for the driver. The glove box door
also incorporates a recessed latch handle. Removal of
the glove box provides access to the passenger airbag,
the glove box lamp and switch, the radio antenna
coaxial cable, the heating and air conditioning vac-
uum harness connector, and additional instrument
panel wiring.
Removal of the instrument panel cluster bezel
allows access to the headlamp switch, instrument
cluster, radio, passenger airbag on-off switch, heated
seat switches (if equipped), and the heating and air
conditioning control. Removal of the instrument clus-
ter allows access to the cluster illumination and indi-
cator bulbs, and more of the instrument panel
wiring. Complete instrument panel removal is
required for service of most components internal to
the heating and air conditioning system housing,
including the heater core and the evaporator.
See the owner's manual in the vehicle glove box for
more information on the features, use and operation
of all of the components and systems mounted on or
in the instrument panel.
BR/BEINSTRUMENT PANEL SYSTEM 23 - 105
INSTRUMENT PANEL SYSTEM (Continued)

A/C Diagnosis
Condition Possible Causes Correction
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.
2. Refrigerant flow
through the accumulator
is restricted.2. (Refer to Plumbing/Accumulator/ Removal/Installation)
in this group. Replace the restricted accumulator, if
required.
3. Refrigerant flow
through the a/c
evaporator is restricted.3. (Refer to Plumbing/A/C Evaporator/ Removal/
Installation) in this group. Replace the restricted
evaporator, if required.
4. Faulty compressor. 4. (Refer to Plumbing/A/C Compressor/ Removal/
Installation) in this group. Replace the compressor, if
required.
24 - 4 HEATING & AIR CONDITIONINGBR/BE
HEATING & AIR CONDITIONING (Continued)

SPECIFICATIONS
A/C APPLICATION TABLE
Item Description Notes
Vehicle BR/BE - Ram Pickup
System R134a w/orifice tube
Compressor Sanden SD7H15 SP-20 PAG
oil
Freeze±up
ControlA/C Low Pressure
Switchaccumulator
mounted
Low psi
Controlopens < 22-24 psi
resets > 37-43 psi
High psi
Controlswitch - opens > 450
- 490 psi, resets <
270 - 330 psimounted on
discharge
line, near
compressor
A/C Heater
Control Headmanual type
Mode Door vacuum actuatorItem Description Notes
Blend Door electric actuator
Recirculation
Doorvacuum actuator
Blower Motor hardwired to control
headresistor block
Cooling Fan viscous fan
Clutch
Control relay PCM
Draw 2 - 3.9 amps @ 12V60.5V @
70É F
Gap 0.0169- 0.0319
DRB IIIT
Reads TPS, RPM, A/C
switch test
Actuators clutch relay
TORQUE SPECIFICATIONS
TORQUE SPECIFICATIONS
DESCRIPTION N´m Ft. Lbs. In. Lbs.
A/C COMPRESSOR CLUTCH PLATE NUT 14.4 10.5 -
A/C COMPRESOR LINE MANIFOLD
FASTENER22 - 200
A/C COMPRESSOR TO MOUNTING
BRACKET BOLTS24 - 210
ACCUMULATOR RETAINING BAND 4.5 - 40
BLOWER MOTOR SCREWS 2.2 - 20
CHECK VALVE AND NIPPLE UNIT (DIESEL) 24 18 -
CONDENSER MOUNTING SCREWS/NUTS 10.5 - 95
DISCHARGE LINE TO CONDENSER
FASTENER20 - 180
DOOR ACTUATOR SCREWS 2.2 - 20
HVAC HOUSING SCREWS 2.2 - 20
HVAC HOUSING TO DASH PANEL NUTS
(ENGINE SIDE)7-60
HVAC HOUSING TO DASH PANEL NUTS
(PASSENGER COMPARTMENT SIDE)4.5 - 40
24 - 8 HEATING & AIR CONDITIONINGBR/BE
HEATING & AIR CONDITIONING (Continued)

CONTROLS
TABLE OF CONTENTS
page page
CONTROLS
DIAGNOSIS AND TESTING.................10
VACUUM SYSTEM......................10
A/C COMPRESSOR CLUTCH
DESCRIPTION...........................13
OPERATION.............................13
DIAGNOSIS AND TESTING.................13
A/C COMPRESSOR CLUTCH COIL.........13
STANDARD PROCEDURE..................13
A/C COMPRESSOR CLUTCH BREAK-IN.....13
REMOVAL..............................14
INSPECTION............................16
INSTALLATION...........................16
A/C COMPRESSOR CLUTCH RELAY
DESCRIPTION...........................17
OPERATION.............................17
DIAGNOSIS AND TESTING.................17
A/C COMPRESSOR CLUTCH RELAY........17
REMOVAL..............................18
INSTALLATION...........................18
A/C HEATER CONTROL
DESCRIPTION...........................18
OPERATION.............................18
DIAGNOSIS AND TESTING.................19
A/C HEATER CONTROL..................19
REMOVAL..............................19
INSTALLATION...........................20
A/C HIGH PRESSURE SWITCH
DESCRIPTION...........................20
OPERATION.............................20
DIAGNOSIS AND TESTING.................20
A/C HIGH PRESSURE SWITCH............20
REMOVAL..............................21
INSTALLATION...........................21
A/C LOW PRESSURE SWITCH
DESCRIPTION...........................21
OPERATION.............................21
DIAGNOSIS AND TESTING.................21
A/C LOW PRESSURE SWITCH............21
REMOVAL..............................21INSTALLATION...........................22
BLOWER MOTOR RELAY
DESCRIPTION...........................22
OPERATION.............................22
DIAGNOSIS AND TESTING.................22
BLOWER MOTOR RELAY.................22
REMOVAL..............................23
INSTALLATION...........................23
BLOWER MOTOR RESISTOR BLOCK
DESCRIPTION...........................23
OPERATION.............................23
DIAGNOSIS AND TESTING.................24
BLOWER MOTOR RESISTOR BLOCK.......24
REMOVAL..............................24
INSTALLATION...........................24
BLOWER MOTOR SWITCH
DESCRIPTION...........................24
OPERATION.............................25
DIAGNOSIS AND TESTING.................25
BLOWER MOTOR SWITCH...............25
REMOVAL..............................25
BLEND DOOR ACTUATOR
REMOVAL..............................25
INSTALLATION...........................26
MODE DOOR ACTUATOR
REMOVAL..............................26
INSTALLATION...........................27
RECIRCULATION DOOR ACTUATOR
REMOVAL..............................27
INSTALLATION...........................28
VACUUM CHECK VALVE
DESCRIPTION...........................28
OPERATION.............................28
REMOVAL..............................29
INSTALLATION...........................29
VACUUM RESERVOIR
DESCRIPTION...........................29
OPERATION.............................29
REMOVAL..............................30
INSTALLATION...........................30
BR/BECONTROLS 24 - 9

A/C COMPRESSOR CLUTCH
DESCRIPTION
The compressor clutch assembly consists of a sta-
tionary electromagnetic coil, a hub bearing and pul-
ley assembly, and a clutch plate (Fig. 4). The
electromagnetic coil unit and the hub bearing and
pulley assembly are each retained on the nose of the
compressor front housing with snap rings. The clutch
plate is mounted to the compressor shaft and secured
with a nut.
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 low pressure switch, the a/c high pres-
sure switch, the compressor clutch relay, and the
Powertrain Control Module (PCM). The PCM may
delay compressor clutch engagement for up to thirty
seconds. Refer to Electronic Control Modules for
more information on the PCM controls.
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
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

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/c
low pressure switch, and the a/c high pressure
switch.
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 7565 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. 14 CLUTCH PLATE INSTALL
Fig. 15 CHECK CLUTCH AIR GAP
1 - FEELER GAUGE
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.
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-
Fig. 16 COMPRESSOR CLUTCH RELAY
TERMINAL LEGEND
NUMBER IDENTIFICATION
30 COMMON FEED
85 COIL GROUND
86 COIL BATTERY
87 NORMALLY OPEN
87A NORMALLY CLOSED
Fig. 17 POWER DISTRIBUTION CENTER
1 - COVER
2 - POWER DISTRIBUTION CENTER
24 - 18 CONTROLSBR/BE
A/C COMPRESSOR CLUTCH RELAY (Continued)

(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.
(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 7565 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).
(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.
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
24 - 22 CONTROLSBR/BE
A/C LOW PRESSURE SWITCH (Continued)