Seats: Description and Operation

INTRODUCTION
A six-way driver side power seat is an available factory-installed option for this model. The power seat system receives battery feed through a fuse in the Power Distribution Center and a circuit breaker in the fuseblock module at all times.

The power seat system is protected by a 30 amp circuit breaker located in cavity CB2 of the fuse block. This circuit breaker is HOT at all times. Circuit A7 is the power supply for the circuit breaker.

The A7 circuit originates in the Power Distribution Center (PDC) and is protected by a 50 amp fuse located in cavity 1.

Circuit F37 is the feed for the switches and the seat motors from the circuit breaker. A bus bar internal to the switches feeds all the contacts. Grounding for the seats is provided on circuit Z3.

SYSTEM OPERATION
Power Seat Switch
The power seat can be adjusted in six different ways using the power seat switch. The switch is located on the lower inboard side of the seat cushion frame.

The individual switches in the power seat switch module cannot be repaired. If one switch is damaged or faulty, the entire power seat switch module must be replaced.

Power Seat Adjuster And 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 different motors. They can be raised or lowered independently of each other. When the center 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 center 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 path to the motor(s) are reversed through the switch contacts. 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 power seat adjuster and motors cannot be repaired, and are serviced only as a complete unit. If any component in this unit is faulty or damaged, the entire power seat adjuster and motors assembly must be replaced.

Circuit Breaker
An automatic resetting circuit breaker in the fuse- block module is used to protect the power seat system circuit. The circuit breaker can protect the system from a short circuit, or from an overload condition caused by an obstructed or stuck seat adjuster.

The circuit breaker cannot be repaired and, if faulty, it must be replaced.

CIRCUIT OPERATION
When the operator selects the FRONT VERTICAL UP function, power is passed on the F37 circuit through the CLOSED contacts in the switch to the P19 circuit. The P19 circuit connects to the motor. Ground is provided on the P21 circuit back to the switch. A ground bus bar internal to the switch then connects it to ground on the Z3 circuit.

For FRONT VERTICAL DOWN function the circuits are reversed. P21 is the feed, and P19 is the ground.

When the operator selects the HORIZONTAL FORWARD function, power is passed on the F37 circuit through the CLOSED contacts in the switch to the P15 circuit. The P15 circuit connects to the motor. Ground is provided on the P17 circuit back to the switch. A ground bus bar internal to the switch then connects to the Z3 circuit.

For HORIZONTAL REARWARD function the circuits are reversed. P17 is the feed, and P15 is the ground.

When the operator selects the REAR VERTICAL UP function, power is passed on the F37 circuit through the CLOSED contacts in the switch to the P11 circuit. The P11 circuit connects to the motor. Ground is provided on the P13 circuit back to the switch. A ground bus bar internal to the switch then connects to the Z3 circuit.

For VERTICAL DOWN function the circuits are reversed. P13 is the feed, and P11 is the ground.