Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
SYS.OK|MANUAL.DB● LIVE
HOMESERVICE MANUALSCHEVROLET2003TRAILBLAZER 4WD L6-4.2L VIN SREPAIR AND DIAGNOSISTRANSMISSION AND DRIVETRAINTRANSFER CASETESTING AND INSPECTIONSYMPTOM RELATED DIAGNOSTIC PROCEDURESTRANSFER CASE - NVG 226-NP8TRANSFER CASE SHIFT CONTROL SWITCH INOPERATIVE
2003 Chevrolet TrailBlazer 4WD L6-4.2L VIN S
Transfer Case Shift Control Switch Inoperative
2003 Chevrolet TrailBlazer 4WD L6-4.2L VIN SSECTION Transfer Case Shift Control Switch Inoperative
Transfer Case Shift Control Switch Inoperative
Circuit Description
The range/mode switch circuit consists of the following 5 switches:
^ 4HI
^ AUTO 4WD
^ 2HI
^ 4LO
^ Neutral
The transfer case shift control module supplies a regulated 5 volts DC to the switch through the 5 volt regulator circuit. The current travels through the resistor of the currently active switch. The switch then returns current to the transfer case shift control module through the switch signal circuit.
The transfer case shift control module constantly monitors this signal voltage to determine the condition of the mode switch circuit.
When each switch is depressed, the switch completes a circuit through the respective resistor. The transfer case shift control module continuously monitors the switch input to determine which of the following buttons were selected:
^ 4HI
^ AUTO 4WD
^ 2HI
^ 4LO
Test Description
The numbers below refer to the step numbers on the diagnostic table.
2. This step tests the functionality of the mode switch.
3. This step tests the modules ability to operate the transfer case modes.
Transfer Case Shift Control Switch Inoperative
Circuit Description
The range/mode switch circuit consists of the following 5 switches:
^ 4HI
^ AUTO 4WD
^ 2HI
^ 4LO
^ Neutral
The transfer case shift control module supplies a regulated 5 volts DC to the switch through the 5 volt regulator circuit. The current travels through the resistor of the currently active switch. The switch then returns current to the transfer case shift control module through the switch signal circuit.
The transfer case shift control module constantly monitors this signal voltage to determine the condition of the mode switch circuit.
When each switch is depressed, the switch completes a circuit through the respective resistor. The transfer case shift control module continuously monitors the switch input to determine which of the following buttons were selected:
^ 4HI
^ AUTO 4WD
^ 2HI
^ 4LO
Test Description
The numbers below refer to the step numbers on the diagnostic table.
2. This step tests the functionality of the mode switch.
3. This step tests the modules ability to operate the transfer case modes.
Transfer Case Shift Control Switch Inoperative
RENDER: 1.0x
NO RELATED
Recommended Tools & Savings
Use the Manual With the Right Hardware
Pair factory procedures with proven DIY tools so the instructions are easier to execute.
Affiliate disclosure: We may earn a commission at no extra cost to you.
When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.