Description And Operation Accumulator; Blower Motor; Blower Motor Relay; Blower Motor Resistor - Jeep Wrangler 1999 Electronic Service Manual

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DESCRIPTION AND OPERATION
ACCUMULATOR
The accumulator is mounted in the engine com-
partment between the evaporator coil outlet tube and
the compressor inlet. Refrigerant enters the accumu-
lator canister as a low pressure vapor through the
inlet tube.
Any liquid, oil-laden refrigerant falls to the bottom
of the canister, which acts as a separator. A desiccant
bag is mounted inside the accumulator canister to
absorb any moisture which may have entered and
become trapped within the refrigerant system (Fig.
2).
Fig. 2 Accumulator - Typical

BLOWER MOTOR

The blower motor and blower wheel are located in
the passenger side end of the heater-A/C housing,
below the glove box. The blower motor controls the
velocity of air flowing through the heater-A/C hous-
ing by spinning a squirrel cage-type blower wheel
within the housing at the selected speed. The blower
motor and wheel can be removed through an opening
in the engine compartment side of the dash panel
without heater-A/C housing removal.
HEATING AND AIR CONDITIONING
The blower motor will only operate when the igni-
tion switch is in the On position, and the heater-A/C
mode control switch knob is in any position, except
Off. The blower motor receives a ground feed at all
times. The blower motor battery feed circuit is pro-
tected by a fuse in the fuseblock module for all
blower speeds except high. The high speed battery
feed circuit is protected by a fuse in the Power Dis-
tribution Center (PDC). Blower motor speed is con-
trolled by regulating the battery feed through the
blower motor switch, blower motor resistor, and a

blower motor relay.

The blower motor and blower motor wheel cannot
be repaired and, if faulty or damaged, they must be
replaced. The blower motor and blower wheel are ser-
viced only as a unit.
BLOWER MOTOR RELAY
The blower motor relay is a International Stan-
dards Organization (ISO)-type relay. The relay is a
electromechanical device that switches battery cur-
rent to the blower motor.
When the blower motor switch is in any position
except off, and the ignition is turned on, the blower
motor relay is energized and provides battery feed to
the blower motor from a fuse in the fuseblock module
through the blower motor resistor.
The blower motor relay coil is controlled by a volt-
age signal from the blower motor switch. See Blower
Motor Relay in the Diagnosis and Testing section of
this group for more information.
The blower motor relay is installed in a wire har-
ness connector located near the passenger side out-
board end of the heater-A/C housing in the passenger
compartment, next to the heater-A/C wire harness
connector.
The blower motor relay cannot be repaired and, if
faulty or damaged, it must be replaced.

BLOWER MOTOR RESISTOR

The blower motor resistor is mounted to the bot-
tom of the heater-A/C housing on the passenger side
of the vehicle under the instrument panel. It can be
accessed for service by removing the heater-A/C
housing kick cover.
The resistor has multiple resistor wires, each of
which reduce the current flow to the blower motor, to
change the blower motor speed. The blower motor
switch directs battery current to the correct resistor
wire to obtain the selected speed. When the highest
blower motor speed is selected, the blower motor is
directly connected to battery current, bypassing the
blower motor resistor.
The blower motor resistor cannot be repaired and,
if faulty or damaged, it must be replaced.
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