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VA
BLOWER MOTOR SWITCH (Continued)
DIAGNOSIS AND TESTING
Before testing the rear blower motor switch, verify
that the front A/C system is functional by performing
the ATC Fuction Test using the DRBIII
Use a volt/ohmmeter to test the rear blower motor
switch. For circuit descriptions and diagrams, refer
to the appropriate wiring information. The wiring
information includes wiring diagrams, proper wire
and connector repair procedures, details of wire har-
ness routing and retention, connector pin-out infor-
mation and location views for the various wire
harness connectors, splices and grounds.
WARNING: ON VEHICLES EQUIPPED WITH AIR-
BAGS, DISABLE THE AIRBAG SYSTEM BEFORE
ATTEMPTING ANY STEERING WHEEL, STEERING
COLUMN, OR INSTRUMENT PANEL COMPONENT
DIAGNOSIS OR SERVICE. DISCONNECT AND ISO-
LATE THE BATTERY NEGATIVE (GROUND) CABLE,
THEN WAIT TWO MINUTES FOR THE AIRBAG SYS-
TEM CAPACITOR TO DISCHARGE BEFORE PER-
FORMING FURTHER DIAGNOSIS OR SERVICE. THIS
IS THE ONLY SURE WAY TO DISABLE THE AIRBAG
SYSTEM. FAILURE TO TAKE THE PROPER PRE-
CAUTIONS COULD RESULT IN ACCIDENTAL AIR-
BAG DEPLOYMENT AND POSSIBLE PERSONAL
INJURY.
(1) Disconnect and isolate the battery negative
cable.
(2) Unplug the wire harness connector from the
rear blower motor switch.
(3) Check for continuity between terminal 10 and
terminals 1, 7 and 4 of the blower motor switch. In
all instances, there should be continuity.
NOTE: To check the switch's internal circuits, con-
nect the negative lead of the ohmmeter to terminal
10 and the positive ohmmeter lead to terminals 1, 7
and 4. To check the switch's integral light emitting
diodes, reverse the ohmmeter leads.
(4) Check for continuity between the rear blower
motor switch terminals 3 and 7 as you move the
blower motor switch to each of the two speed posi-
tions, and the Off position. There should be continu-
ity in only one blower motor switch speed position.
(5) Check for continuity between the rear blower
motor switch terminals 4 and 8 as you move the
blower motor switch to each of the two speed posi-
tions, and the Off position. There should be continu-
ity in only the other blower motor switch speed
position.
(6) If OK, test and repair the rear blower motor
switch wire harness circuits. If not OK, replace the
faulty rear blower motor switch.
REMOVAL
NOTE: The rear blower motor switch is used only
on models with the optional rear A/C unit.
scan tool.
(1) Disconnect and isolate the battery negative
cable.
(2) Remove the blower motor switch from the
switch panel.
(3) Disconnect the wire harness connector from the
rear blower motor switch and remove the switch from
the vehicle.
INSTALLATION
(1) Connect the wire harness connector to the rear
blower motor switch.
(2) Install the blower motor switch into the switch
panel.
(3) Reconnect the battery negative cable.
BLOWER MOTOR RELAY
DESCRIPTION
The blower motor relays are an International Stan-
dards Organization (ISO)-type relay. The relays are
electro-mechanical devices which when energized,
directs fused battery current to the rear blower
motor. The relay coils are energized when they
receives a voltage signal from the blower motor
switch.
OPERATION
When the rear blower motor switch is in the low
speed position, the switch directs a voltage signal to
the high side of rear blower relay #1 and energizes
its relay coil. When energized, the low side of blower
relay #1 directs fused battery current through an
integral blower resistor to the rear blower motor.
When in the high speed position, the rear blower
switch directs a voltage signal to the high side of
rear blower relay #2 and energizes its relay coil.
When energized, the low side of blower relay #2
directs fused battery current through an integral
blower resistor to the rear blower motor.
The rear blower motor relays are located in the
relay block of the rear evaporator housing. Refer to
the appropriate wiring diagrams for more informa-
tion.
The blower motor relay cannot be repaired and, if
faulty or damaged, it must be replaced.
CONTROLS - REAR 24 - 23
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