Town & Country AWD V6-3.8L VIN L (2003)
is electronically controlled and continuously monitored for malfunctions. Power is supplied through pin 27 of the FCM connector.
Front Washer Motor
The front washer switch is a direct input to the BCM. The BCM sends a PCI Bus message to the FCM informing it of a request to wash. The front
washer motor is then powered through low side control inside the FCM. This circuit is electronically controlled and continuously monitored for
malfunctions. In addition, the FCM electronically protects the washer motor from system voltages higher than 16 volts by automatically switching off
the low side circuit. The low side circuit is connected to pin 45 in the FCM connector.
Rear Washer Motor
The rear washer switch is a direct input to the BCM. The BCM sends a PCI Bus message to the FCM informing it of a request to wash. The rear
washer motor is then powered through low side control inside the FCM. This circuit is electronically controlled and continuously monitored for
malfunctions. In addition, the FCM electronically protects the washer motor from system voltages higher than 16 volts by automatically switching off
the low side circuit. The low side circuit is connected to pin 46 in the FCM connector.
Cabin Heater
When the ignition is in Run, the FCM monitors the PCI bus for the Cabin Heater Activation request. The Automatic or Manual Temperature Control
initiates this request only when all conditions for the Cabin Heater activation are favorable. The request carries the status bit that the FCM requires to
activate its Cabin Heater Assist Control output. This output is a low side driver (coming from FCM pin 15) which supplies a ground signal to the
Cabin Heater (pin 5). When the Cabin Heater receives this ground signal input, it interprets this as an activation signal. The FCM low side driver is
also capable of diagnostic sensing. The driver will sense an open circuit when the driver is off, and will sense a short to voltage when the driver is on.
The FCM will set DTCs for both of these types of faults. For additional information, refer to Cabin Heater under General Information and Diagnostic
Procedures in the manual.
Brake Shift Interlock System
The brake shift interlock solenoid receives power from both high side and low side controls inside the FCM. The high side control is on the same
circuit as the EATX module power, and the low side control comes through pin 47 of the FCM connector. The solenoid is controlled by the low side
driver when the brake pedal is pressed. Both circuits are continuously monitored for malfunctions.
Relay Controls
RELAY CONTROLS
Fog Lamp Relay
The fog lamp switch is a direct input to the BCM. The BCM sends a PCI Bus message to the FCM informing it to turn on the fog lamp relay. The fog
lamp relay is then powered through low side control on pin 33 of the FCM. This circuit is electronically controlled and continuously monitored for
malfunctions. Fog lamp functionality is not equipped on all vehicles. The FCM "learns" that the vehicle is equipped with fog lamps by reading the
BCM PCI Bus message.
Park Lamp Relay
The park lamp switch is a direct input to the BCM. The BCM sends a PCI Bus message to the FCM informing it to turn on the park lamp relay. The
park lamp relay is then powered through low side control on pin 13 of the FCM. This circuit is electronically controlled and continuously monitored
for malfunctions.
Front Wiper ON Relay
The front wiper switch is a direct input to the BCM. The BCM sends a PCI Bus message to the FCM informing it to turn on the front wiper on relay.
The front wiper on relay is then powered through low side control on pin 14 of the FCM. This circuit is electronically controlled and continuously
monitored for malfunctions.
Front Wiper High/low Relay
The front wiper switch is a direct input to the BCM. The BCM sends a PCI Bus message to the FCM informing it to turn on the front wiper high/low
relay. The relay switches power between the low speed and high speed windings of the wiper motor. The front wiper high/low relay is powered
through low side control on pin ~4 of the FCM. This circuit is electronically controlled and continuously monitored for malfunctions.
Accessory Relay
The accessory relay works in conjunction with the FCM's power accessory delay feature to control the operation of the radio, power windows, washer
motors, wiper motors and power outlet. The accessory relay is turned on through low side control on pin 35 of the FCM. This circuit is electronically
controlled and continuously monitored for malfunctions. Depending on the ignition switch position, the accessory relay will remain on or will time-out
and turn off. The accessory relay remains on in the RUN and ACCY positions of the ignition switch. In the UNLK and OFF positions, the relay will
remain energized for 45 seconds then turn off. During this time-out period, if the driver or passenger doors are opened, the relay will turn off
immediately. While the ignition switch is in the START position, the relay will also drop-out, then resume operation. Accessory relay operation is
most noticeable by observing the operation of the radio or blower functions.
Horn Relay
The horn relay operates through a direct wire input to the FCM from the horn switch (FCM pin 17), or a PCI Bus message from the BCM. The relay
responds to the horn switch, remote door lock and VTA alarm functions. The horn relay is powered through low side control on pin 10 of the FCM.
Under normal operating conditions, if the horn is pressed for longer than 30 seconds, the FCM will automatically deactivate the horn to prevent
