Hombre S Regular Cab 4WD V6-4.3L (1999)
Transfer Case Actuator: Description and Operation
Motor and Relay Voltage Checks
Whenever the electric-shift motor is turned ON or OFF the motor and the electrical circuits are tested both in the de-energized and energized
condition. If one or both voltage relays fail to detect the proper voltage after energizing or de-energized and energized condition.If one or both of the
voltage relays fail to detect the proper voltage after energizing or de- energizing, the shift is aborted by the TCCM and a DTC of 3 is stored in order to
indicate a faulty TCCM motor circuit.
If one or both relays fail to detect the proper voltage after de- energizing, both relays are turned ON by the TCCM, (even with the ignition switch
positioned OFF) in order to prevent the motor from running. The TCCM then stores a DTC of 3 in order to indicate a faulty TCCM motor circuit. All
of the status lamps blink three times, stop, and repeat the blinking continuously in order to alert the driver that the electronic shift system requires
immediate repair.The battery will drain when this condition occurs, regardless of the ignition switch position.
Motor/Encoder Circuit Operation
The TCCM operates the motor/encoder in one direction by energizing one relay while the second relay is de-energized. The TCCM operates the motor
in the reverse direction by energizing the second relay while the first relay is de-energized. The encoder part of the motor/encoder sends shift
positioning signals to the TCCM.
The motor/encoder converts a shaft position, representing a mode of range selection, into electrical signals for use by the TCCM. By interpreting the
four channels (P, A, B, C) of the encoder, the transfer case control module can detect what position the transfer case is in 2HI, 4HI, 4LO, or in
transition between any of the two.
The four hall effect sensors of the motor/encoder are used for channels (A, B, Cycles if, and P). These sensors provide a path to ground when a magnet
passes over them. A rotating magnetic ring causes the hall effect sensors voltage to drop from 5 to 0 volts. The TCCM detects the voltage of all the
channels and interprets the current transfer case shift position.
