What does it mean?
B1674 is a Body (airbags, seat belts, body electronics) fault code. It indicates: Driver Courtesy Lamp Control Circuit High .
Symptoms
- Driver footwell or door courtesy lamp stays dark when the door is opened
- Interior lighting works everywhere else, which points to a single circuit
- The lamp works occasionally, usually when the door is at a certain angle
- No illuminated entry on the driver side at night
- The fault appeared after door trim, speaker or window regulator work
Likely causes
- Courtesy lamp bulb burned out or the lamp assembly removed
- Open circuit in the door harness, typically broken strands inside the flexing boot between the door and the body
- Lamp connector unplugged or a terminal pushed out after door trim work
- Corroded contacts in the lamp holder so the bulb no longer makes contact
- LED interior lamp fitted whose current draw the module cannot detect
- Short to battery on the control wire from an incorrectly connected accessory
- Open output driver in the body control module
How to fix it
- Open the driver door and check the lamp, then fit a known good bulb or a known good lamp assembly
- Inspect the lamp holder contacts for corrosion and lost spring tension
- Check that the connector is fully seated and that no terminal has been pushed out of the housing
- With the door open, measure the voltage at the lamp connector while the module commands the lamp on
- Flex the wiring inside the door to body boot while measuring continuity, since broken strands hide inside intact insulation
- Remove any LED conversion and test with an original type bulb
- Repair the broken wire with staggered joints, then test the door several times before clearing the code