Seats: Description and Operation

POWER SEAT
The memory power seat provides the driver with 2 position settings for the left seat. Each power seat motor is connected to the MHSMM with two circuits. Each circuit is switched between battery and ground. By alternating the circuits the MHSMM controls the movement of the motors based on input from the power seat switch or through memory recall.

Each motor contains a potentiometer to monitor the seat position. To monitor the position of the motor, the MHSMM sends out a 5-volt reference on the sensor supply circuit. The sensor is grounded back to the module on a common ground circuit. Based on the position of the sensor, the MHSMM monitors the voltage change through the sensor on a separate signal circuit.

The MHSMM stores the input value of each of the four seat potentiometers in memory when the system is requested. The driver can initiate memory recall, using either the seat mounted memory switch or the RKE transmitter. When initiated, the MHSMM adjusts the four seat motors to match the memorized seat position data.

For safety, the memory seat recall is disabled by the MHSMM when the vehicle is out of park position. Any obstruction to seat movement over a 2 second delay will cause the seat to stop moving in which case a stalled motor would be detected by the MHSMM which would then flag a trouble code and the corresponding seat output would be deactivated. However, if the object obstructing the seat is removed, the seat will function normally again.

MEMORY SEAT GLIDE
The intent of this feature is to allow for easier entry and exit to the vehicle by moving the seat rearward a short distance when the operator turns the ignition OFF. The seat returns to its original position when the operator returns and turns ON the ignition or extends the seat belt. If any seat movement is initiated, whether manual or by memory recall, after the ignition has been turned OFF, that will cancel any ensuing glide to enter movement until the next ignition cycle.

This feature can be enabled/disabled by the owner by holding the memory set button and simultaneously pressing the horizontal rearward switch. To reinstate the feature, repeat the process. This can also be done using the DRB which will also inform as to which state it is in.

HEATED SEATS
The controls for the heated seats are located on the side of each seat. The system offers two seat temperature settings of approximately 98.6 F (LO) and approximately 107.6 F (HI).

As the temperature in the seat rises, the Negative Temperature Coefficient (NTC) resistance decreases and the voltage reading detected by the MHSMM increases. The seat heater output is deactivated once the voltage reading reaches it's upper threshold for either setting, high or low.

As the temperature decreases, the voltage reading decreases until the lower threshold is reached for either setting high or low. At this point the seat heat output is activated once again and this cycle repeats itself as long as the seat heat request is ON. The thresholds for low and high settings are preprogrammed into the MHSMM memory.

The heated seat switch contain resistors pulled up to ignition which are processed by the MHSMM as voltage readings indicating desired heat setting high or low.