Grand Caravan AWD V6-3.8L VIN L (2001)
Power Mirror Control Module: Description and Operation
MEMORY SYSTEM
The memory system consists of power driver's seat, power mirrors and radio presets. The Memory Seat/Mirror Module (MSMM) is located under
the driver's seat. It receives input from the following: driver's manual 8-way seat switch, driver's seat position sensors, PCI bus circuits, and the
power mirror sensors. The module uses these inputs to perform the following functions: position the driver's memory seat, both exterior mirrors
(during recalls), and send/receive the memory system information over the PCI bus.
The Memory Set Switch is wired to the Body Control Module (BCM). When a button (either #1 or #2) is pressed on the set switch causes the to
BCM send a message to the MSMM which in turn sends a motion status messages to the BCM. If the BCM receives no motion from the MSMM it
will send a recall message to the MSMM and radio (once ignition is in run or accessory). The MSMM will in turn position the drivers seat, both
mirrors along with recalling the radio presets. If the drivers seat or either exterior mirror is inoperative from its own respective switches, use the
service information and schematic to diagnose the problem. This manual addresses the memory problems only and it is assumed there is not a
basic component failure.
Memory Mirrors
Each outside mirror contains vertical and horizontal bi-directional drive positioning motors and position sensors. The MSMM provides a 5-volt
reference on the signal circuit to each position sensor. The sensors share a common ground circuit. The MSMM monitors the position of the mirror
motors by measuring the voltage on each signal circuit. When a memory position is set, the MSMM monitors and stores the position of the outside
mirrors. The MSMM adjusts the mirrors to the appropriate positions when a memory recall message is received from the RKE or is requested from
the memory set switch.
The power mirror switch during non-memory operation operates both mirrors independently of the MSMM.
