Circuit/System Description

The transfer case motor is a bi-directional, permanent magnet, D.C. motor. When energized, through motor control A or motor control B, the ground is provided by the opposing motor control circuit which becomes grounded through the transfer case shift control module (TCCM) ground circuit. The motor, through a series of gears, rotates the actuator lever shaft which moves the mode and range forks in order to shift the transfer case between the following modes/ranges:

• 4HI
• 4HI Lock
• 4LO Lock
• Neutral

The TCCM tests both motor circuits for unexpected voltage by suppling a 2.8-4.0 V diagnostic voltage on each of the motor circuits and reading the return voltage back on the other circuit.