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Home >> Chevrolet >> 2002 >> Blazer 4D Utility, 4WD, Part Time >> Repair and Diagnosis >> External Pages >> Different car >> Section 1435 (Transfer Case - NVG 226-NP8) >> Diagnostic Information and Procedures >> Transfer Case Shift Control Switch Indicator Always On - Two or More >> Test Description

Test Description

WARNING: This page is about a different car, the 2004 GMC Envoy XUV, 2004 GMC Envoy XL, 2004 GMC Envoy, and 2004 Chevrolet TrailBlazer. However, it is still accessible from the selected car via links, so may be relevant.

The numbers below refer to the step numbers on the diagnostic table.

  1. 2:  This step tests the transfer case electrical control of the lamp circuits.
  2. 3:  This step helps determine a short to ground in the suspect lamp circuits.
  3. 4:  This step tests the suspect lamp circuits for a short to ground.
  4. 5:  This step repairs a short to ground in the suspect lamp circuit.
Transfer Case Shift Control Switch Indicator Always On - Two or More

Step Action Yes No
1
IMPORTANT: If the transfer case shift control switch is left between the 4HI and 4LO mode detents, the transfer case defaults to the AWD mode. This is considered a characteristic of the system. Ensure the switch is within the proper detents.
Did you perform the Diagnostic System Check - Transfer Case?		 Go to Step 2  Go to Diagnostic System Check - Transfer Case 
2 
  1. Turn the ignition ON, with the engine OFF.
  2. Install a scan tool.
  3. Using a scan tool, command all the indicator lamps OFF.
Do all the lamps go OFF?		 Go to Step 7  Go to Step 3 
3 
  1. Using a scan tool, determine the transfer case mode.
  2. Use this information to determine which lamp circuits are at fault.
  3. Disconnect the transfer case shift control switch.
  4. Test the suspect lamp circuits for a short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.
Is the suspect circuits shorted to ground?		 Go to Step 4  Go to Step 6 
4 
  1. Disconnect the transfer case shift control module.
  2. Test the suspect lamp circuits for a short to ground. Refer to Testing for Short to Ground and Wiring Repairs in Wiring Systems.
Is the suspect circuits shorted to ground?		 Go to Step 5  Go to Step 7 
5  Repair short to ground in the suspect lamp circuit. Refer to Wiring Repairs in Wiring Systems.
Did you find and correct the condition?		 Go to Step 8  -
6 Replace the mode switch. Refer to Transfer Case Shift Control Switch Replacement (GMC, Buick)  or Transfer Case Shift Control Switch Replacement (Chevrolet)  .
Did you complete the repair?		 Go to Step 8  -
7
IMPORTANT: After transfer case shift control module replacement and reprogramming, ensure all doors are closed and the key is out of the ignition, then open and close the doors again and wait 2 minutes to avoid incomplete programming or false communication DTCs.
Replace the transfer case shift control module. Refer to Transfer Case Shift Control Module Replacement and Transfer Case Control Module Reprogramming  .Did you complete the repair?		 Go to Step 8  -
8
  1. Use the scan tool in order to clear the DTCs.
  2. Operate the vehicle in order to determine if the symptom has been corrected.
Is the symptom still present?		 Go to Step 2  System OK
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