What does it mean?
B1673 is a Body (airbags, seat belts, body electronics) fault code. It indicates: Driver Courtesy Lamp Control Circuit Low .
Symptoms
- Driver side courtesy or footwell lamp does not light when the door is opened
- The lamp stays on all the time and drains the battery overnight
- Interior lighting fuse blows and takes other interior lamps with it
- Illuminated entry and the delayed switch off no longer work correctly
- Lamp flickers or dims when the door is moved on its hinges
Likely causes
- Short to ground in the courtesy lamp wiring inside the driver door, most often in the flexible loom between the door and the A pillar where the wires break and touch the door shell
- Water running down inside the door and reaching the lamp connector or the wiring boot
- Corroded or crushed courtesy lamp holder in the door trim or footwell
- Lamp assembly damaged when the door trim was removed or refitted
- Aftermarket interior lighting or an added accessory connected to the courtesy lamp circuit
- Wiring pinched behind the trim panel by a clip or a screw
- Shorted output driver in the body control module
How to fix it
- Watch the courtesy lamp status and the door ajar input on live data while opening and closing the driver door
- Disconnect the courtesy lamp and see whether the code still sets, which separates the lamp from the harness
- Peel back the rubber boot between the door and the body and flex the wires by hand, looking for broken insulation and copper showing through
- With the connector disconnected, measure the resistance between the control wire and ground; a low value proves a short to ground
- Inspect the wiring behind the door trim panel for clips or screws that have pierced the loom
- Remove any aftermarket interior lighting fitted to this circuit
- Repair the broken wires individually with staggered joints so the loom stays flexible, then test the door repeatedly and clear the code