Test Description

WARNING: This page is about a different car, the 2004 GMC Sierra, 2004 GMC Cab & Chassis Sierra, 2004 Chevrolet Silverado, and 2004 Chevrolet Cab & Chassis Silverado. 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.

2: This step inspects for the visual operation of the neutral Indicator. Command both the ON and OFF states.
3: This step tests for voltage at the neutral indicator feed side of the transfer case select switch.
4: This step verifies that the transfer case shift control module is providing ground to the neutral Indicator.
5: This step tests if ground is constantly being applied to the neutral indicator.
6: This step tests the control circuit of the neutral indicator for a short to voltage or an open.
7: This step tests the control circuit of the neutral indicator for a short to ground.

DTC B0790

Step	Action	Yes	No
Schematic Reference: Transfer Case Control Schematics Connector End View Reference: Transfer Case Control Connector End Views
1	Did you perform the Diagnostic System Check - Transfer Case?	Go to Step 2	Go to Diagnostic System Check - Transfer Case
2	Install a scan tool. Turn the ignition ON, with the engine OFF. With the scan tool, command the neutral control ON and OFF. Does the neutral turn ON and OFF with each command?	Go to Testing for Intermittent Conditions and Poor Connections in Wiring Systems	Go to Step 3
3	Turn the ignition OFF. Remove the transfer case select switch. Disconnect the connector on the transfer case select switch. Turn the ignition ON. Probe the ignition 3 voltage circuit with a DMM that is connected to a good ground. Does the DMM indicate battery voltage?	Go to Step 4	Go to Step 10
4	Connect a DMM between the harness connector of the neutral indicator control circuit and the ignition 3 voltage circuit. With the scan tool, command the neutral indicator ON and OFF. Does the DMM indicate battery voltage and then 0 volts with each command?	Go to Step 8	Go to Step 5
5	Does the DMM continue to indicate battery voltage with each command?	Go to Step 7	Go to Step 6
6	Test the neutral indicator control circuit for a short to voltage or an open. Refer to Testing for Continuity and Wiring Repairs in Wiring Systems. Did you find and correct the condition?	Go to Step 13	Go to Step 9
7	Test the control circuit of the neutral indicator for a short to ground. Refer to Testing for Short to Ground and Wiring Repairs in Wiring Systems. Did you find and correct the condition?	Go to Step 13	Go to Step 9
8	Disconnect the transfer case shift control module connectors C1 and C2. Inspect for poor connections at the transfer case shift control switch. Refer to Testing for Intermittent Conditions and Poor Connections and Wiring Repairs in Wiring Systems. Did you find and correct the condition?	Go to Step 13	Go to Step 11
9	Inspect for poor connections at the harness connector of the transfer case shift control module. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition?	Go to Step 13	Go to Step 12
10	Repair the ignition 3 voltage circuit of the transfer case select switch for an open, high resistance or short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you complete the repair?	Go to Step 13	-
11	Replace the transfer case select switch. Refer to Transfer Case Shift Control Switch Replacement . Did you complete the repair?	Go to Step 13	-
12	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 13	-
13	Use the scan tool in order to clear the DTCs. Operate the vehicle within the Conditions for Running the DTC as specified in the supporting text. Does the DTC set?	Go to Step 2	System OK