RAM 1500 Truck 4WD V8-5.9L VIN Z (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 Instrument Cluster (MIC) and can be read with the DRB III. The switches are a multiplexed signal to the MIC. 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 MIC 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 MIC. The ground must be
complete so that the switches can cause the voltage drop for the MIC to see. The circuit passes through the clockspring so continuity through this devise
must be verified.
