Circuit/System Testing
WARNING: This page is about a different car, the 2007 GMC Sierra and 2007 Chevrolet Silverado. However, it is still accessible from the selected car via links, so may be relevant.
Check the interior dimming circuit pin 2 at the transfer case shift control switch for voltage for the 2 seconds after turning the ignition on during the bulb check.
- If less than battery voltage check the interior lights dimming circuit for an open or high resistance. If the voltage is low or non existent and the circuit tests good replace the BCM. If the interior dimming circuit and BCM test good go to the next step.
- If the 4 low indicator is on at all times check the 4 low indicator control circuit for a short to ground. If the 4 low indicator is inoperative during bulb check, check the 4 high indicator control circuit for an open or high resistance or short to voltage. If the circuit checks good continue to the next step.
- With the ignition on shift the transmission to neutral and using transfer case output controls attempt to command the 4 low indicator off and on. If the 4 low indicator is still inoperative short to 4 low indicator control to ground, if the 4 low indicator lights replace the module, program, and complete the motor learn procedure. If the 4 low indicator is still inoperative replace the switch.