B1480

DTC B1480

CIRCUIT DESCRIPTION
The body control module (BCM) supplies battery positive voltage to the reading lamps and both visor vanity mirror lamps. In the event that any of these lamps were to remain illuminated for more than 20 minutes with the ignition switch in the OFF position, the BCM will deactivate the inadvertent power courtesy lamps supply voltage circuit to prevent a total battery discharge condition.

DTC DESCRIPTOR
This diagnostic procedure supports the following DTC:

DTC B1480 Battery Rundown Protection Circuit

CONDITIONS FOR RUNNING THE DTC
The battery voltage must be between 9-16 volts.

CONDITIONS FOR SETTING THE DTC
- The inadvertent power courtesy lamps supply voltage circuit to the reading lamps and both visor vanity mirror lamps is shorted to ground for more than 1 second.
- There is a loss of the rear fuse block truck body controller (TBC) 4 battery supply voltage to the BCM for more than 1 second while one or more of the lamps in the inadvertent power circuit have been activated.

ACTION TAKEN WHEN THE DTC SETS
The reading lamps and both visor vanity mirror lamps will not operate.

CONDITIONS FOR CLEARING THE MIL/DTC
- This DTC will clear on current status after the condition for setting the fault is corrected.
- A history DTC will clear after 100 consecutive ignition cycles without a fault present.
- History and current DTCs can be cleared using a scan tool.

DIAGNOSTIC AIDS
Perform a visual inspection for loose or poor connections at all related components. Refer to Testing for Intermittent Conditions and Poor Connections. Component Tests and General Diagnostics

TEST DESCRIPTION

Step 1 - Step 9:

The numbers below refer to the step numbers on the diagnostic table.
2. This step test determines if an open or short to ground exists.
3. This step test determines if a short to ground exists in the lamp wiring or internally within the BCM.
4. This step test determines if an open exists in the body wiring harness extension harness or internally within the BCM.
8. After replacement of the BCM you must calibrate the new module for proper operation.