Originally Posted by gmcandcaprice

i wouldnt worry about that as long as every thing works on the interior but heres the pinpoint test

DTC B2615
Circuit Description
The body control module (BCM) receives a ground signal from the door jamb, lift glass/lift gate if equipped, or courtesy lamp switches requesting courtesy/dome lamp illumination. When this occurs, the BCM directly sends a voltage through the courtesy lamp supply voltage circuit illuminating the courtesy/dome lamps.

Voltage for the courtesy lamp supply voltage circuit as well as the backup lamp supply voltage circuit is from the left instrument panel fuse block TBC 2B 15-amp fuse directly through the BCM to these circuits.

DTC Descriptor
This diagnostic procedure supports the following DTC:

DTC B2615 Passenger Compartment Dimming 2 (courtesy Lamps, etc.) Circuit

Conditions for Running the DTC
The battery voltage must be between 9.0-16.0 volts.

Conditions for Setting the DTC
When the BCM receives a courtesy lamp illumination request signal and the courtesy lamp supply voltage circuit is shorted to ground.
When the BCM is not receiving a courtesy lamp illumination request signal and the courtesy lamp supply voltage circuit is open only to the first splice from the BCM or the circuit is shorted to voltage.
There is a loss of the instrument panel fuse block TBC 2B battery supply voltage to the BCM for 1 second.
Action Taken When the DTC Sets
The courtesy dome lamps will not operate or are always ON.

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 and Poor Connections in Wiring Systems.
An open circuit up to the first splice only, from the BCM, will set the DTC.
A short to ground on the backup lamp supply voltage circuit, courtesy lamp supply voltage circuit OR the TBC 2B battery positive voltage circuit to the BCM will open the TBC 2B fuse in the left instrument panel fuse block.
Test Description
The numbers below refer to the step numbers on the diagnostic table.

This step test determines if the problem exists in the wiring or the BCM.

This step test determines if the problem exists in the wiring or the BCM.

After replacement of the BCM you must calibrate the new module for proper operation.

Step
Action
Yes
No

Schematic Reference: Interior Lights Schematics

Connector End View Reference: Lighting Systems Connector End Views or Computer/Integrating Systems Connector End Views in Computer/Integrating Systems

1
Did you perform the Diagnostic System Check - Vehicle?
Go to Step 2
Go to Diagnostic System Check - Vehicle in Vehicle DTC Information

2
Inspect the TBC 2B fuse in the instrument panel fuse block.

Is the fuse open?
Go to Step 3
Go to Step 4

3
Test the following circuits for a short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems:

Courtesy lamp supply voltage
Backup lamp supply voltage
TBC 2B battery positive voltage to the body control module (BCM)
Did you find and correct the condition?
Go to Step 6
Go to Step 5

4
Test the courtesy lamp supply voltage circuit for the following conditions:

An open
A short to voltage
High resistance Refer to Circuit Testing and Wiring Repairs in Wiring Systems.
Did you find and correct the condition?
Go to Step 6
Go to Step 5

5
Replace the BCM. Refer to Control Module References in Computer/Integrating Systems for replacement, setup, and programming.

Did you complete the replacement?
Go to Step 6
--

6
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 reset?
Go to Step 2
System OK

Originally Posted by gmcandcaprice

try to follow that the best you can usally its somethin simple (An open circuit up to the first splice only, from the BCM, will set the DTC.
A short to ground on the backup lamp supply voltage circuit) maybe a start do all the lights work properly if so i wouldnt go spend money

let me know if this helps