Circuit Description

WARNING: This page is about a different car, the 2003 GMC Yukon XL, 2003 GMC Yukon, 2003 Chevrolet Tahoe, 2003 Chevrolet Suburban, and 2003 Cadillac Escalade ESV. However, it is still accessible from the selected car via links, so may be relevant.

The indicator lamps circuit consist of 3 individual lamps contained inside the mode switch assembly. They are AWD, 4LO and Neutral. The AWD and 4LO, are contained inside their respective mode button. When the ignition in ON, the transfer case shift control module illuminates the indicator lamp that corresponds to the current ATC gear position by providing a ground through a current limiting driver.

The transfer case shift control module flashes each indicator lamp after a shift has been requested and will continue to flash until the transfer case shift control module can complete the shift.

A solid state circuit located inside the switch supplies ignition voltage to the lamps. The solid state circuit also receives voltage whenever the headlamp switch is in the parklamp or headlamp position. When the solid state circuit receives voltage from the headlamp switch it will reduce the voltage that it supplies to the indicator lamps, dimming the lamps when the headlamps are ON.