Controlled Power Feeds
- Front Airbag System
The FCM provides power to the Occupant Restraint Control (ORC) system through two "fuseless" circuits (ORC RUN/START, and ORC RUN only). These circuits are electronically controlled and continuously monitored for malfunctions. Power is supplied while the ignition switch is in the RUN and START positions on pin No. 48 of the FCM connector, and in the RUN position on pin No. 29.
- Side Airbag System
The FCM provides power to the Side Impact Airbag Control Module (SIACM) system through one "fuseless" circuit. This circuit is electronically controlled and continuously monitored for malfunctions. Power is supplied in the ignition RUN and START positions on pin No. 28 of the FCM connector.
- Headlamp Power
The headlamp switch is a direct input to the BCM. The BCM sends a PCI Bus message to the FCM informing it of a headlamp switch status change. The FCM then turns on power to the headlamps through four "fuseless" circuits. These circuits are electronically controlled and continuously monitored for malfunctions. Power is supplied to each filament in a separate circuit (right hand low on pin No. 6, right hand high on pin No. 4, left hand low on pin No. 3 and left hand high on pin No. 5). For vehicles equipped with Daytime Running Lamps (DRL), the FCM electronically steps down the headlamp voltage to provide the desired illumination.
- EATX Power
The electronic automatic 4 speed transmission module is powered when the ignition switch is in the UNLOCK, RUN or START positions. This circuit is electronically controlled and continuously monitored for malfunctions. Power is supplied through pin No. 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 No. 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 No. 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 A/C-Heater Control Module 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 No. 15) which supplies a ground signal to the Cabin Heater (pin No. 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.
- 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 No. 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.