Accessory Switch Transfer Case Mode Indicator Flashes in 2WD Mode
Accessory Switch Transfer Case Mode Indicator Flashes in 2WD Mode
Circuit Description
The Isuzu T150 transfer case contains a 2WD/4WD switch, which is supplied battery voltage by the transfer case shift control module. When the transfer case mode selection is in either 4WD low or 4WD high the 2WD/4WD switch provides a path to ground, pulling the 2WD/4WD signal circuit low. This assists the transfer case shift control module in determining the present mode. A fault in the 2WD/4WD signal circuit, or the neutral switch signal circuit will cause the 2WD mode indicator to flash. A fault in the front axle actuator or the corresponding front axle actuator circuits can also cause the 2WD mode indicator to flash. In the 2WD mode the switch is open and the voltage on the 2WD/4WD signal circuit is battery voltage.
Diagnostic Aids
- Check the inline connector C105 for proper connection, bent pins, damage, or corrosion. Refer to Harness Routing Views and Delphi Connectors.
- Check the transfer case shift control module connectors C1 and C2 for proper connection and bent or corroded pins or terminals. Refer to Repairing Connector Terminals.
- Check for water leaks at doors and bulkhead areas. Refer to Waterleak Test Preparation. Waterleak Test Preparation
- Check the 2WD/4WD switch for proper connection, bent pins, or damaged terminals. Refer to Transfer Case Control Component Views.
Test Description
The number below refers to the step number on the diagnostic table.
2. This step determines if the front axle actuator is causing the symptom.
5. This step determines if a short to ground on the 2WD/4WD switch signal circuit is causing the symptom.
6. This step determines if a short to ground on the neutral switch signal circuit is causing the symptom.
