Right Low Beam Circuit Malfunction
The B2503 code indicates that the Body Control Module (BCM) or Headlamp Control Module (HCM) has detected a fault in the right front low beam circuit. This typically results from an open circuit, short to ground, or short to battery voltage in the wiring or component supplying the right low beam bulb or ballast.
1. Commonly Affected Makes
2. Most Common Causes
- Blown or incorrect right low beam bulb
- Faulty right HID/Xenon ballast (if equipped)
- Damaged, corroded, or shorted wiring in the right headlamp circuit
- Loose, broken, or backed-out pins in the right headlamp connector
- Blown fuse for the right low beam circuit
- Faulty BCM or HCM with damaged internal driver
3. Symptoms You Will Notice
- Right low beam inoperative
- Warning light on dashboard (e.g., headlamp indicator)
4. Step-by-Step Diagnosis
Inspect the right low beam bulb for filament breakage or incorrect type; replace if needed.
Check the right low beam fuse and replace if blown.
Visually inspect wiring and connector at the right headlamp for damage, corrosion, or loose pins.
Test for voltage and ground at the bulb connector with the low beams on.
If equipped with HID, test the ballast by swapping with the left side (if accessible) or using a known-good unit.
If all above checks pass, suspect a faulty BCM/HCM and perform module diagnostics.
5. Frequently Asked Questions
Is it safe to drive?▼
Driving with only one low beam is unsafe, especially at night, and may be illegal. You should repair it promptly.
How much does it cost to fix?▼
Costs range from $20 for a bulb to $500+ for a BCM replacement, depending on the root cause.