GM Service Manual Online
For 1990-2009 cars only

The driver and passenger power seat systems each consist of a seat switch and 4 reversible motors (front vertical, rear vertical, horizontal, and recline) that operate independently of each other. Each motor contains an electronic circuit breaker (PTC) that will reset only after voltage has been removed from the motor. Battery positive voltage (B+) is supplied at all times to each seat switch from the rear fuse block PWR SEAT circuit breaker.

Horizontal

When the seat switch is operated to move the entire seat forward, battery positive voltage (B+) is applied via the entire seat forward switch contacts and the entire seat forward control circuit to the horizontal motor. The motor is grounded via the entire seat backward switch contacts and the entire seat backward control circuit to the motor. The motor runs in order to drive the seat forward until the switch is released. Moving the entire seat backward works similarly to moving the entire seat forward except that battery positive voltage (B+) and ground are applied on opposite circuits causing the motor to run in the opposite direction.

Rear Vertical

When the seat switch is operated to tilt the seat rear vertical up, battery positive voltage (B+) is applied via the rear vertical up switch contacts and the rear vertical up control circuit to the rear vertical motor. The motor is grounded via the rear vertical down switch contacts and the rear vertical down control circuit to the motor. The motor runs in order to drive the rear of the seat up until the switch is released. Tilting the seat rear vertical down works similarly to tilting the seat rear vertical up except that battery positive voltage (B+) and ground are applied on opposite circuits causing the motor to run in the opposite direction.

Front vertical

When the seat switch is operated to tilt the seat front vertical up, battery positive voltage (B+) is applied via the front vertical up switch contacts and the front vertical up control circuit to the front vertical motor. The motor is grounded via the front vertical down switch contacts and the front vertical down control circuit to the motor. The motor runs in order to drive the front of the seat up until the switch is released. Tilting the seat front vertical down works similarly to tilting the seat front vertical up except that battery positive voltage (B+) and ground are applied on opposite circuits causing the motor to run in the opposite direction.

Entire Seat Up or Down

When a seat switch is operated in order to move the entire seat to the up position, battery positive voltage (B+) is applied via both the front vertical up and rear vertical up switch contacts, through the front and rear vertical up control circuits to both vertical motors. The motors are grounded via the front and rear vertical down switch contacts and the front and rear vertical down control circuits to the motors. Both motors run in order to drive the entire seat up until the switch is released. Moving the entire seat down works similarly to moving the entire seat up except that battery positive voltage (B+) and ground are applied on the opposite circuits causing the motor to run in the opposite direction.

Recline

When the seat switch is operated to recline the seat back forward, battery positive voltage (B+) is applied via the recline forward switch contacts and the recline forward control circuit to the recline motor. The motor is grounded via the recline backward switch contacts and the recline backward control circuit to the motor. The motor runs in order to recline the seat back forward until the switch is released. Moving the recline backward works similarly to moving the recline forward except that battery positive voltage (B+) and ground are applied on the opposite circuits causing the motor to run in the opposite direction.