RAM 1500 Truck 2WD V8-4.7L VIN N (2002)
A button located on the HVAC control head controls the Heated Mirror Relay, which is located in the IPM. The HVAC control will ground the Heated
Mirror Relay Control circuit to energize this relay. The relay control circuit is continuously monitored for certain malfunctions that the HVAC will report
as DTC's.
Exterior Lighting System
EXTERIOR LIGHTING SYSTEM
The Instrument Cluster monitors the Headlamp Switch and Multifunctions Switch on its MUX line. The Instrument Cluster sends a PCI bus message to
the Front Control Module (FCM) to actuate the Headlamps ON when the ignition switch is ON and when an open or short failure occurs on the
headlamps switch input circuit to the instrument cluster. If the exterior lamps are left ON and the ignition switch OFF for more than 3 minutes, the
Instrument Cluster will send a PCI bus message to the FCM to turn the exterior lamps OFF. This feature prevents the battery from being discharged
when the Exterior Lamps have been left ON.
Front Control Module
FRONT CONTROL MODULE
The Front Control Module (FCM) is a microprocessor-based electrical control and interface center located in the engine compartment. When it is mated
to the Power Distribution Center (PDC), it is referred to as the Integrated Power Module (IPM). The IPM, with its fuses and relays provides power and
signal distribution throughout most of the vehicle. The FCM receives hard-wired analog and resistor multiplexed inputs as well as digital electronic
inputs from other electronic modules in the vehicle electrical system through its connection to the IPM and the Programmable Communications Interface
(PCI) data bus network. Based on these inputs and programming, the FCM uses high side drivers to provide direct power feeds and low side drivers to
provide relay control for some of the vehicle's most critical electrical systems.
The FCM provides the following features:
Controlled Feeds
Headlamp power
Windshield washer pump motor
Relay Controls
Accessory relay
Adjustable pedals relay (when equipped)
Fog lamp relay (when equipped)
Horn relay
Park lamp relay
Wiper ON/OFF relay
Wiper high/low relay
Electrical Inputs
Headlamp battery supplies
Module battery supply
Power ground
Ignition switch RUN or START position status
Ignition switch START Only status
PCI bus
Brake lamp switch
Wiper park switch
Washer fluid level switch
Brake fluid level switch
Ambient Temperature sensor
Right park lamp outage
Left park lamp outage
Battery IOD
Battery (+) connection detection
Flash reprogramming voltage
Controlled Power Feeds
Headlamp Power