Stuck in 4WD, 4WD light flashing

Hi,

It could be a few things. Do me a favor. I attached a pic below which shows several different conditions. If you can identify which you feel is most relevant to your problem, I can get you the diagnostic flow chart. Most of the flow chart will require a digital multi meter to test, but there are a few that require a scanner which can actuate different components via the data link connector.

If I attached all the flow charts available, it would drive you crazy. That's why I'm asking specifically which you feel is most relevant.

Let me know.

Joe

Hi,

That's a good question. I would suspect it is the actuator going bad. However, you really can't check it again until it happens. Or, you could run 12v battery voltage to the actuator to see if it works properly.

Do you still need the flow chart?

Joe

Not a problem, Jeff. Here are the directions. The attached picture is a continuation of the test procedure.

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2006 Chevy Truck Colorado 4WD L5-3.5L VIN 6
Isuzu T150 - Transfer Case
Vehicle Transmission and Drivetrain Transfer Case Testing and Inspection Symptom Related Diagnostic Procedures Accessory Switch Transfer Case Mode Indicator Flashes In 4WD High or 4WD Low Mode Isuzu T150 - Transfer Case
ISUZU T150 - TRANSFER CASE
Accessory Switch Transfer Case Mode Indicator Flashes in 4WD High or 4WD Low 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 4WD low or 4WD high mode indicators to flash. A fault in the front axle actuator or the corresponding front axle actuator circuits can also cause the 4WD low or 4WD high mode indicators to flash.

Diagnostic Aids
Check the inline connector C105 for proper connection, bent pins, damage, or corrosion. Refer to Harness Routing Views. See: Vehicle > Harness
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. See: Vehicle > Component Tests and General Diagnostics
Check for water leaks at doors and bulkhead areas. Refer to Waterleak Test Preparation. See: Body and Frame > Symptom Related Diagnostic Procedures > 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.
4. This step determines if the 2WD/4WD switch is causing the symptom.
5. This step determines if an open 2WD/4WD signal circuit is causing the symptom.
6. This step determines if a shorted to ground neutral switch signal circuit is causing the symptom.

Step 1 - Step 9

See pic 1

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If you need anything else, don't be afraid to ask.

Take care and let me know what you find.

Joe