PINPOINT TEST C : Power-Stow Seat Motor and Sensor Functional Test - LH: Notes

Refer to Power Seats for schematic and connector information.

Normal Operation and Fault Conditions 

The PFSM supplies voltage and ground to the power-stow seat motor to move the seat to and from the STOW position when selected by the seat control switch. When STOW is selected from NORMAL, the backrest folds forward to release the spring loaded headrest. If an obstruction is detected in the STOW range of movement, the seat stops, reverses movement a few inches and then stops again until the obstruction is removed. When the obstruction has been removed, the seat control switch must be pressed again to reset the request. The seat goes to the power-stow seat motor home position (seat folded and latched to the floor) and then continues with the STOW request. If the PFSM detects an open or short in the power-stow seat motor circuitry, motor operation is disabled. If a short to ground is present, the motor works in only one direction.

A Hall-effect sensor is located inside each of the power-stow seat motor assemblies to detect power-stow seat motor movement and position to the PFSM. If the sensor does not detect motor movement during a request from the seat control switch, the PFSM disables the power-stow seat motor output. When the seat control switch is pressed again, the seat moves in short increments indicating a fault with the sensor or circuitry.

Visual Inspection and Diagnostic Pre-checks 

Verify good battery condition before diagnosing the PFSM system. Poor battery condition may interfere with PFSM operation. If battery voltage drops below 10 volts, seat movement does not start. If battery voltage drops below 8 volts, a started seat movement stops.