B2615 on Cadillac: How to Diagnose & Fix
Passenger Compartment Dimming 2 Circuit
1 Cadillac model · 1 documented issue · $150-$600 repair
B2615 on Cadillac by model: symptoms, diagnosis and fix
XTS HID/Xenon headlamps suffer ballast (HID control unit) failures and headlight-housing condensation that cause intermittent or total loss of a low beam. Owners report flickering, a headlamp that cuts out then comes back, or a dead side after a new bulb. Moisture entering the housing is a frequent root cause — water reaching the ballast causes rapid failure — and corrosion in the headlight wiring/ground (often shared with the upper LED DRL) can take out both the ballast and DRL together.
Common Symptoms
- One low-beam HID out or flickering
- Headlight cuts out then comes back
- Condensation/water inside headlamp
- Upper DRL out on the same side
- New bulb still doesn't fix it
- Pinkish/dim HID color before failure
How to Fix
Diagnose by swapping the D3S bulb side-to-side; if the fault follows the position, the ballast/igniter is bad, not the bulb. Replace the failed HID ballast/control module and reseal the housing; dry out and re-gasket any housing showing condensation. Inspect the ballast connector and chassis ground for corrosion and repair before installing new parts, or the new ballast will fail again. Use OEM-grade D3S bulbs and a matching ballast to avoid color/flicker issues.
Sources for this issue (1)
B2615 code reference
General diagnostic-code context. The code alone does not confirm a cause for your vehicle; use the applicable issue card and its sources.
Frequently asked questions
What does B2615 mean on a Cadillac?
B2615 stands for "Passenger Compartment Dimming 2 Circuit." General Motors body code. The body control module supplies battery voltage to the interior courtesy, dome, and reading lamps and sets B2615 when that circuit does not behave as commanded - typically a short to ground, a short to voltage, or an open in the dome/courtesy lamp control circuit, or a loss of battery supply to the BCM from the instrument panel fuse block. Symptoms are interior courtesy and dome lamps that stay off entirely, stay on constantly, or flicker, along with erratic interior illumination dimming. It does not trigger the check engine light or affect drivability. Exact set conditions vary by platform, so confirm against the service information for the specific year and model. On Cadillac it is documented across 1 model: XTS.
What are the most common causes of B2615?
The most common causes of B2615 are: Short to ground in the courtesy/dome lamp control wiring, Open circuit or broken wire between the BCM and the lamps, Circuit shorted to voltage, Blown fuse or loss of battery supply at the instrument panel fuse block feed to the BCM, Failed door jamb switch or corroded lamp socket, Faulty body control module (least common). The specific cause varies by vehicle.
How much does it cost to fix B2615 on a Cadillac?
Published repair estimates on Cadillac range from $150 to $600 depending on the model and root cause. If an issue mentions a recall or campaign, check your VIN with the manufacturer or NHTSA and confirm eligibility and coverage with a dealer.
Looking for B2615 on a different make?
View B2615 across all makes →Content compiled with AI assistance using NHTSA complaints, TSBs, and owner reports. May contain errors. Always verify with your vehicle's service manual.