TB9 - Check Harness Circuit(s) For Shorts to Power

- Key "OFF".

- Breakout box installed, Powertrain Control Module (PCM) disconnected.

- Appropriate switch disconnected.

- For 4x4 Low circuit:

- Measure resistance between test pin 12 and test pin 37/57 at the breakout box.

- For Transmission Control Switch (TCS) / Transmission Control Indicator Lamp (TCIL) circuits:

- Measure resistance between test pin 41 and test pins 37/57 at the breakout box.

- Measure resistance between test pin 55 and test pins 37/57 at the breakout box.

- Is each resistance greater than 10,000 ohms?

Yes -- Replace damaged switch, either 4x4L range switch or TCS due to Diagnostic Trouble Code (DTC) received. Remove breakout box. Reconnect PCM. Rerun quick test. Quick Test Appendix (Detailed Testing Instructions)

No -- Service short circuit(s). Remove breakout box. Reconnect all components. Rerun quick test. Quick Test Appendix (Detailed Testing Instructions)