Seats: Description and Operation

POWER SEATS

CIRCUIT OPERATION

Driver's Seat and Passenger's Seat - Manual Operation
There are five reversible Motors that operate the Power Seat. The seat height is controlled by two Motors: one for Front Height and the other for Rear Height; these two Motors operate independently of each other. The other three Motors provide positioning for Headrest Height, Seatback Reclining, and the Entire Seat Forward/Backward.

When any Seat Switch is depressed, a path to ground is provided for two Relays inside the Control Unit. One Relay controls the Motor for the seat function depressed and the other controls the polarity of the voltage to the Motor selected. An example of this action is as follows: The Front Height UP Switch is depressed, energizing the coils of the Front Height and Fwd/Up Relays. The Relay Switch contacts close and voltage is applied to the Front Height Motor. This drives the front of the seat up as long as the Front Height UP Switch is depressed, or until end of travel. When the Front Height Down Switch is depressed, the Front Height and the Back/Down Relays are energized. Polarity to the motor is reversed, which drives the seat down. The operation of the other seat functions is similar to the operation of the Front Height control.

Driver's Seat - Memory Operation
When operating the Memory Seats from the Seat Switches, operation is the same as the non- memory seats. When the memory functions are operated, the appropriate relays are grounded through the Solid State circuits of the Control Unit rather than the Seat Switches.

Operation of the Memory Seat requires the Ignition Switch to be in ACCY or RUN.

The Memory Seat operates by storing voltages at the Motor Position Inputs of the Memory Seat Control Module. Voltage is applied to the Front Height Motor Position Sensor at terminal 1 and grounded through terminal 3. The input voltage of the Motor Position Sensor is supplied to the Memory Control Module through terminal 2. The input voltage will vary between 1 and 5 volts depending upon the location of the Front Height Motor. The Motor Position Sensor circuits of the other Seat Motors are similar to the Front Height Motor circuit. When any one of the Memory Select buttons is pressed, the Memory Control Module applies voltage to the Motors until the Memory Position Sensor input voltages equal those previously stored.

To store a seat position in memory, move the seat to the desired position and depress one of the three Memory Store Switches. The green LED will flash when the position is accepted in memory. When the Ignition is in ACCY or RUN and the engine is not running, the Memory Select Switches can be pressed momentarily to move the seat to a memory position. As the seat is moving to a memory position, the green LED will light until the seat reaches that position. When the engine is running, the desired Memory Select Switch must be depressed and held. During this Memory Seat operation, the green LED will flash until the seat has reached the position stored.

When the Stop Switch is depressed, memory functions are disabled. This action will disable the memory prior to and during memory positioning. Memory positioning will also be disrupted if any other Memory Select Switch is depressed during positioning.

When a fault occurs in the Memory Seat System, the red LED will flash after depressing any of the Memory Select Switches.