Seats: Description and Operation
POWER SEAT SYSTEMDESCRIPTION
The power seat system allows the driver and front seat passenger to electrically adjust their seating positions using the power seat switches located on the outboard seat cushion side shield of each front seat. A driver side eight-way power seat includes a six-way adjustable seat cushion track and a two-way power seat back. The driver power seat can be adjusted up, down, front up, front down, forward, rearward, recliner forward, and recliner rearward. A passenger side four-way power seat includes a two-way adjustable seat cushion track and a two-way power seat back. The passenger power front seat can be adjusted forward, rearward, recliner forward and recliner rearward. The power seat system is also available with the heated seat option and memory seat option that automatically positions the power seat for two different drivers.
The power seat system for this vehicle includes the following major components:
- Power Seat Adjuster - The power seat adjuster is made up of the upper and lower power seat adjuster assemblies. The driver upper power seat adjuster contains two reversible motors that are connected to worm-drive gearboxes that move the seat adjuster through a combination of screw-type drive units. These motors are the height adjust motor and the front tilt motor. On vehicles equipped with non-memory power seats, each motor contains a self-resetting circuit breaker to protect it from overload. On vehicles equipped with memory power seats the motor overload protection is a function of the Memory Seat Module (MSM). Consecutive or frequent resetting of the circuit breakers may damaged the motors. There are no motors on the passenger upper power seat adjuster.
The height adjust motor is located on the rear of the upper power seat adjuster assembly and controls the up and down movement of the entire seat. The height adjust motor can be serviced separately from the power seat adjuster assembly.
The front tilt motor is located on the front of the upper power seat adjuster assembly and controls the up and down movement of the seat front only. The front tilt motor can be serviced separately from the power seat adjuster assembly.
The driver and passenger lower power seat adjusters contain one reversible motor that is connected to a worm-drive gearbox that moves the seat adjuster through a screw-type drive unit. On vehicles equipped with non-memory power seats, the motor will contain a self-resetting circuit breaker to protect it from overload. On vehicles equipped with memory power seats the motor overload protection is a function of the Memory Seat Module (MSM). Consecutive or frequent resetting of the circuit breakers may damaged the motors. The motor is part of the lower power seat track unit and must be replaced as an assembly.
- Power Seat Recliner - The power seat recliner replaces the manual seat recliner. The power seat option includes an electrically operated power seat back recliner mechanism.
The power seat recliner switch is integral to the power seat switch assembly, but is actuated with a separate switch knob.
The power seat recliner motor assembly is mounted in the place of a seat hinge on the outboard side of the seat. The upper hinge plate of the power seat recliner mechanism is secured with two screws to the seat back frame and is concealed beneath the seat back trim cover and padding. The lower hinge plate and the motor and drive unit of the power seat recliner mechanism is secured with two screws to the seat cushion frame, and is concealed by the outboard seat cushion side shield.
The power seat recliner motor cannot be repaired. If the unit is inoperative or damaged, the seat back frame must be replaced.
- Power Seat Switches - Vehicles may be equipped with driver only, or driver and passenger power seat switches. One seat switch is used for each front seat. The power seat switches are paddle-type levers mounted on the outboard seat side shields. Movement of the seat cushions and backs mimics the action of the switch paddles.
OPERATION
The power seat system receives battery current through a 50 amp fuse in the Power Distribution Center (PDC) so that the power seats remain operational, regardless of the ignition switch position.
When a power seat switch is actuated, a battery feed and a ground path are applied through the power seat switch contacts to the appropriate motor or motors. The motor and drive unit operate to move the seat in the selected direction until the switch is released, or until the travel limit of the power seat track is reached. When the switch is moved in the opposite direction, the battery feed and ground path to the motor is reversed through the switch contacts. This causes the motor to run in the opposite direction.