Grand Caravan FWD V6-3.3L VIN 3 Flex Fuel (2002)
Remote Control: Description and Operation
REMOTE RADIO CONTROLS
These radios can be controlled via remote radio switches (optional). These switches are located on the back side of the steering wheel. They control
mode, preset, seek up, seek down, volume up and volume down functions.
These functions are inputs to the Body Control Module and can be read with the DRB III under "body computer". The switches are a multiplexed
signal to the BCM. The radio control MUX circuit is a 5 volt line that is pulled to ground through different value resistors built into the switches. This
causes a voltage drop to be seen by the BCM and it sends a specific message to the radio on the PCI Bus circuit. The radio then responses to the
message.
This circuit is fairly simple to troubleshoot. The circuit must be complete from the switches in the steering wheel to the BCM. The ground must be
complete so that the switches can cause the voltage drop for the BCM to see. The circuit passes through the clockspring so continuity through this
devise must be verified.
