Circuit Description
WARNING: This page is about a different car, the 2002 GMC Envoy XL, 2002 GMC Envoy, and 2002 Chevrolet TrailBlazer. However, it is still accessible from the selected car via links, so may be relevant.
The range/mode switch circuit consists of five switches. The transfer case shift control module supplies a regulated 5 volts, DC to the switch through the 5 V Reg circuit. The current travel through the resistor of the currently active switch. It then returns current to the transfer case shift control module through the switch signal circuit.
The transfer case shift control module constantly monitors this signal voltage to determine the condition of the mode switch circuit.
When each of the switches is depressed they will complete a circuit through their own specific resistor. The transfer case shift control module continuously monitors the switch input to determine whether the 4HI, AUTO 4WD, 2HI, or 4LO button was selected by the driver.