GM Service Manual Online
For 1990-2009 cars only

Power Lumbar System Components

    • Seat lumbar switch
    • Seat lumbar motor
    • PWR SEAT circuit breaker 25 amp

Power Lumbar Description and Operation

The seat lumbar switch is supplied with battery positive voltage from the PWR SEAT circuit breaker located in the I/P fuse block. The seat lumbar switch contains forward and rearward adjustment switches that are normally open to ground. The seat lumbar switch provides both power and ground to the lumbar motor. When the seat lumbar switch is operated to the forward position, battery voltage is applied through the forward switch contacts to the lumbar motor forward control circuit. The lumbar motor rearward control circuit supplies ground through the switch contacts of the rearward switch to G301. The motor will operate to move the lumbar support forward toward the occupant's back until the lumbar is fully extended or the lumbar switch is released. Operating the seat lumbar switch to the rearward position reverses this process. Voltage is applied through the contacts of the rearward switch to the lumbar motor through the lumbar motor rearward control circuit. The lumbar motor forward control circuit supplies ground for the circuit through G301. The motor will operate to move the lumbar support rearward away from the occupant's back until the lumbar is fully retracted or the lumbar switch is released. The lumbar motor contains an internal electronic circuit breaker (PTC) that will open if the motor overheats or binds. The circuit breaker will reset when voltage has been removed from the lumbar motor.