Description And Operation; Power Lumbar Adjuster/Motors; Power Lumbar Switch; Power Recliner Adjuster/Motors - Jeep 1996 Grand Cherokee Service Manual

8R - 2 POWER SEAT SYSTEMS
DESCRIPTION AND OPERATION (Continued)
potentiometers on each of the driver's power seat
motors. The MSM receives messages on the CCD
data bus from the Driver Door Module (DDM) (mem-
ory set/select switch status), the Powertrain Control
Module (PCM) (vehicle speed status), and the Body
Control Module (seat belt switch status). The pro-
gramming in the MSM allows it to process the infor-
mation from these inputs and send control outputs to
each of the driver's power seat motors. The MSM will
prevent the seat memory function from being initi-
ated if the driver's seat belt is buckled, or if the vehi-
cle is moving.
For diagnosis of the MSM or the CCD data bus,
refer to the proper Body Diagnostic Procedures Man-
ual. The MSM cannot be repaired and, if faulty, it
must be replaced.

POWER SEAT SWITCH

The power seat can be adjusted in eight different
ways using the power seat switch. The switch is
located at the lower outboard side of the seat cushion
on the seat cushion side shield.
Refer to the owner's manual for more information
on the power seat switch functions and the seat
adjusting procedures. The individual switches cannot
be repaired. If one switch fails, the entire switch
module must be replaced.

POWER LUMBAR SWITCH

The power lumbar adjuster on each front seat can
be moved in or out electrically by operating the sin-
gle two-way switch mounted near the front of the
outboard seat cushion side shield. The power lumbar
switches cannot be repaired and, if faulty, must be
replaced.

POWER SEAT ADJUSTER/MOTORS

There are three reversible motors that operate the
power seat adjuster. The motors are connected to
worm-drive gearboxes that move the seat adjuster
through a combination of screw-type drive units.
The front and rear of a seat are operated by differ-
ent motors. They can be raised or lowered indepen-
dently of each other. When the seat switch is pushed
to the Up or Down position, both the front and rear
motors operate in unison, moving the entire seat up
or down. The forward-rearward motor is operated by
pushing the seat switch to the Forward or Rearward
position.
When a switch is actuated, a battery feed and a
ground path are applied through the switch contacts
to the motor(s). The motor(s) operate to move the
seat in the selected direction until the switch is
released, or until the travel limit of the power seat
adjuster is reached. When the switch is moved in the
opposite direction, the battery feed and ground paths
to the motor(s) are reversed through the switch con-
tacts. This causes the motor to run in the opposite
direction.
Each motor contains a self-resetting circuit breaker
to protect it from overload. Consecutive or frequent
resetting of the circuit breakers must not be allowed
to continue, or the motors may be damaged. Make
the necessary repairs. The motors used on models
with the optional memory system also have a posi-
tion potentiometer included in the motor assembly.
The power seat adjuster and motors cannot be
repaired, and are serviced only as a complete unit. If
any component in this unit should fail, the entire
assembly must be replaced.

POWER RECLINER ADJUSTER/MOTORS

The power recliner adjuster uses a reversible motor
to operate the seat back recliner adjuster. The motor
is connected to a gearbox that moves the recliner
adjuster through a screw-type drive unit.
When the power recliner switch is actuated, a bat-
tery feed and a ground path are applied through the
switch contacts to the motor. The motor operates to
move the seat back in the selected direction until the
switch is released, or until the travel limit of the
power recliner adjuster is reached. When the switch
is moved in the opposite direction, the battery feed
and ground paths to the motor are reversed through
the switch contacts. This causes the motor to run in
the opposite direction.
The motor contains a self-resetting circuit breaker
to protect it from overload. Consecutive or frequent
resetting of the circuit breaker must not be allowed
to continue, or the motor may be damaged. Make the
necessary repairs. The motors used on models with
the optional memory system also have a position
potentiometer included in the motor assembly.
The power recliner adjuster and motor cannot be
repaired, and is serviced only as a complete unit. If
any component in this unit should fail, the entire
assembly must be replaced.

POWER LUMBAR ADJUSTER/MOTORS

There is a reversible motor that operates the power
lumbar adjuster. The motor is connected to a worm-
drive gearbox that moves the lumbar adjuster mech-
anism through a cable and lever-type actuator unit.
When the power lumbar switch is actuated, a bat-
tery feed and a ground path are applied through the
switch contacts to the motor. The motor operates to
move the lumbar adjuster mechanism in the selected
direction until the switch is released, or until the
travel limit of the lumbar adjuster is reached. When
the switch is moved in the opposite direction, the
battery feed and ground paths to the motor are
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