Operation

OPERATION

The Memory Heated Seat/Adjustable Pedal Module (MHSAPM) controls the heated, power and memory seat systems as well as the adjustable foot pedal system. However different, these systems share some software inside the module. Refer to the following text which explains how the different systems are controlled by the MHSAPM.

FRONT HEATED SEAT SYSTEM OPERATION

When either of the front heated seat switches are depressed a resistor multi-plexed signal is sent to the corresponding door module (Driver or Passenger). The applicable Door Module then sends a message via the Programmable Communications Interface (PCI) data bus network to the MHSAPM, signaling the module to energize the heating element for the selected seat. Light Emitting Diodes (LED) in each switch indicate the level of heat in use. The switch LEDs are controlled by the applicable Door Module.

The MHSAPM energizes an integral solid-state relay, which supplies battery current to the seat heating elements. When high-temperature heating is selected, the heaters provide a boosted heat level during the first four minutes of operation after heating is activated. The heat output then drops to the normal selected-temperature level. If high-level heating is selected, the control system will automatically switch to the low level after two hours of continuous operation. Operation on the low setting turns off only when the ignition switch is turned off or the heated seat switch is pressed a second time indicating an off command.

MEMORY SEAT SYSTEM OPERATION

Depressing any of the drivers front door trim panel mounted, memory seat switches sends a hardwired, resistor multi-plexed signal to the drivers door module. The door module then sends a PCI data bus message to the MHSAPM. The module detects the memory seat switch status via the PCI data bus circuit and energizes the appropriate power seat motors. The programmed software in the MHSAPM allows it to know the location of the seat track by a resistance value generated from the seat track mounted potentiometers. When the correct preset location is achieved the module will de-energize the power seat track motors. The MHSAPM will prevent the seat memory recall function from being initiated if the transmission gear selector lever is not in the Park or Neutral positions, or if the vehicle is moving. These inputs are monitored over the PCI data bus circuit.

ADJUSTABLE FOOT PEDAL SYSTEM OPERATION

Depressing the adjustable foot pedal switch sends a hardwired, resistor multi-plexed signal to the drivers door module. The door module then sends a PCI data bus message to the MHSAPM. The module detects the adjustable pedal switch status via the PCI data bus circuit and energizes the appropriate foot pedal motor. When the foot pedal switch is released the module will stop the motor.

Depressing the memory switch will signal the module to move the pedal assembly to the preprogrammed position. The programmed software in the MHSAPM allows it to know the location of the foot pedal assembly by a resistance value generated from the pedal assembly mounted potentiometer. When the correct preset location is achieved the module will de-energize the foot pedal motor. The MHSAPM will prevent the adjustable foot pedal function from being initiated if the transmission gear selector lever is not in the Park or Neutral positions, or if the vehicle is moving. These inputs are monitored over the PCI data bus circuit also.