The transfer case shift control switch circuit consists of three normally open switches. From the 4WD fuse the switch is supplied with ignition 3 voltage. When one of the switches is pressed, current travels through the switch to its corresponding signal circuit and to the transfer case shift control module. The transfer case shift control module continuously monitors the switch inputs to determine whether the 2HI, 4HI, or 4LO buttons have been selected by the driver.
The numbers below refer to the step numbers on the diagnostic table.
This step tests the functionality of the transfer case shift control switch buttons.
This step tests the transfer case shift control switch for proper function.
This step tests the individual switch signal circuits.
This step tests the transfer case shift control switch ignition 3 circuit for proper voltage.
This step tests the transfer case shift control switch for proper function.
This step determines if the vehicle is equipped with an automatic or manual transmission.
This step tests the A/T shift lock switch supply voltage circuit for proper voltage.
This step repairs an open or high resistance in the A/T shift lock switch supply voltage circuit.
This step tests the suspect switch signal circuit for an open or high resistance.
This step tests the 4WD fuse for an open.
This step repairs an open in the transfer case shift control switch ignition 3 voltage circuit.
This step tests the 4WD fuse to determine if it re-blows.
The step tests the transfer case shift control switch ignition 3 voltage circuit and the transfer case shift control switch signal circuits for a short to ground.
Step | Action | Value(s) | Yes | No |
---|---|---|---|---|
Schematic Reference: Transfer Case Control Schematics | ||||
1 |
Important: The transfer case shift control module is not a class 2 device, and therefore a scan tool can not be utilized on this transfer case. Did you perform A Diagnostic System Check - Transfer Case? | -- | Go to Step 2 | |
Are all of the buttons on the shift control switch working properly? | -- | Go to Testing for Intermittent Conditions and Poor Connections in Wiring Systems | Go to Step 3 | |
Is only one button on the shift control switch inoperative? | -- | Go to Step 4 | Go to Step 5 | |
Does the voltage measure near the specified value? | B+ | Go to Step 11 | Go to Step 16 | |
Does the voltage measure near the specified value? | B+ | Go to Step 6 | Go to Step 12 | |
Does the voltage measure near the specified value for each of the circuits? | B+ | Go to Step 8 | Go to Step 16 | |
7 | Test the 2 HI Switch Signal, 4 HI Switch Signal, and 4 LOW Switch Signal circuits for a short to battery positive. Did you find and correct the problem? | -- | Go to Step 18 | Go to Step 8 |
Is this vehicle equipped with an automatic transmission? | -- | Go to Step 9 | Go to Step 17 | |
Does the voltage measure near the specified value? | B+ | Go to Step 17 | Go to Step 10 | |
Test for an open or high resistance in the A/T shift lock switch supply voltage circuit. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 18 | -- | |
Did you find and correct the condition? | -- | Go to Step 18 | Go to Step 17 | |
Test the 4WD fuse for an open. Was the fuse open? | -- | Go to Step 14 | Go to Step 13 | |
Repair an open in the shift control switch ignition 3 voltage circuit. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you complete the repair? | -- | Go to Step 18 | -- | |
Did the fuse blow again? | -- | Go to Step 15 | Go to Step 18 | |
Test the shift control switch ignition 3 voltage circuit and the selector switch signal circuits for a short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you complete the repair? | -- | Go to Step 18 | -- | |
16 | Replace the shift control switch. Refer to Transfer Case Shift Control Switch Replacement . Did you complete the replacement? | -- | Go to Step 18 | -- |
17 | Replace the transfer case shift control module. Refer to Transfer Case Shift Control Module Replacement . Did you complete the replacement? | -- | Go to Step 18 | -- |
18 | Operate the vehicle within the conditions for causing the symptom as specified in the supporting text. Does the symptom re-occur? | -- | Go to Step 2 | System OK |