Transfer Case Control Switch Indicator Lamps Flash Continuously

Transfer Case Shift Control Switch Indicator Lamps Flash Continuously





Test 1-6

Circuit Description
This symptom is usually the result of actions expected to take place during the transition of a transfer case mode change which has not happened. When the transfer case changes from 2WD to 4WD (for example), the front axle is locked by the transfer case shift control module. If the transfer case shift control module does not sense that the front axle is applied, it waits for the action to take place before the gear change is made. While waiting, the shift control switch indicator will continue to flash -for a period of time, at which time all other mode requests will be ignored for the duration of the ignition cycle.
The front axle control circuit consists of an electric motor actuator which engages and disengages the front axle. The front axle actuator consists of a Permanent Magnetic (PM) motor, a worm gear controlled plunger, a front axle switch and an electronic control circuit all within the actuator assembly.
The front axle actuator has four circuits connected:
^ Ignition 3 voltage circuit
^ Ground circuit
^ Axle actuator control circuit
^ Axle switch signal circuit Whenever a shift to 4HI, or 4LO is requested, the transfer case shift control module engages the front axle by grounding the front axle control circuit through a current limiting driver.

Test Description
The numbers below refer to the step numbers on the diagnostic table.
2. This step determines the position of the front axle actuator.
3. This step helps determine if the front axle will not engage.
4. This step helps determine if the front axle will not disengage.