What does it mean?
B2507 is a Body (airbags, seat belts, body electronics) fault code. It indicates: Telltale Lamp circuit Fault .
Symptoms
- The right high beam does not come on when main beam is selected
- Only the left high beam lights, giving an obviously uneven beam pattern
- The main beam indicator on the cluster behaves oddly
- Automatic high beam assist stops working
- A bulb failure message for the right headlamp
Likely causes
- Right high beam filament blown, or the LED module inside the headlamp has failed
- High resistance in the bulb holder from heat damaged contacts
- Open circuit in the high beam feed or in the shared headlamp ground
- Damaged or corroded headlamp connector after water entered through a cracked lens or a failed seal
- Worn high beam relay contacts on systems that still use a relay
- Incorrect bulb wattage upsetting the module load monitoring
- Failed high beam output stage inside the lighting control module
How to fix it
- Select main beam and confirm visually which side is dead
- Swap the bulb with the working side to check whether the fault follows the bulb
- Measure voltage at the headlamp connector with main beam commanded on, then carry out voltage drop tests on the feed and the ground
- Inspect the connector and the holder for heat damage, discolouration and corrosion caused by a lens or seal leak
- Check the high beam relay where one is fitted by swapping it with an identical relay
- Verify the headlamp earth point is clean and tight
- Replace the bulb, the headlamp assembly or the control module according to what the measurements show, then check beam alignment