Shift Control Switch Indicator Lamps Flash Continuously

Transfer Case Shift Control Switch Indicator Lamps Flash Continuously





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 transfer case encoder motor will rotate clockwise or counterclockwise in order to shift to the proper gear. If the transfer case shift control module does not see the following conditions the shift control switch indicator lamps will continue to flash.
^ The encoder motor has driven to the proper gear position.
^ The front axle indicator switch is closed (received by a signal from the PCM).
^ The vehicle is not moving (received by a signal from the PCM).
^ The Park/Neutral switch has closed or the clutch pedal is fully depressed (providing a ground to the TCCM).

Test Description
The numbers below refer to the step numbers on the diagnostic table.
2. This step tests the operation of the transfer case shift control switch to help determine if the system is operating properly.
3. This step determines if the vehicle speed sensor reading is correct.
4. This step tests the operation of the front axle indicator switch state.
5. This step determines if the park switch reading is correct.