Circuit/System Description

The 2 High indicator circuit consists of a light emitting diode (LED), a LED feed circuit and a LED control circuit. The indicator dimming control circuit is the LED feed circuit and continuously supplies voltage to the 2 High, Auto 4WD, and 4 High LEDs. When the 2 High mode has been selected by the driver, the transfer case shift control module (TCCM) provides a ground through the 2 High indicator control circuit illuminating the LED. The TCCM tests the 2 High indicator circuit for unexpected voltage by monitoring the B+ supplied by the BCM on the indicator dimming control circuit by grounding the 2 High indicator control circuit for 2 seconds during the bulb test at key ON.