Circuit Description
WARNING: This page is about a different car, the 2007 GMC Yukon XL, 2007 GMC Yukon, 2007 Chevrolet Tahoe, 2007 Chevrolet Suburban, and 2007 Chevrolet Avalanche. However, it is still accessible from the selected car via links, so may be relevant.
The 4HI indicator circuit consists of an LED dimming supply circuit and a 4HI indicator control circuit. When the 4HI mode is selected, current is supplied to the 4HI indicator by the LED dimming supply circuit, traveling through the 4HI indicator LEDs, at which time the transfer case shift control module supplies the ground through the 4HI indicator control circuit.