What does it mean?
B1667 is a Body (airbags, seat belts, body electronics) fault code. It indicates: Reverse Lamp Control Circuit Low .
Symptoms
- Reverse lamps do not come on when reverse gear is selected
- Reverse lamps stay on continuously, even with the vehicle moving forward
- Rear lighting fuse blows soon after replacement
- Reversing camera image is dark at night because the reverse lamps are not working
- The fault appears after rain or after a trailer has been connected
Likely causes
- Short to ground in the reverse lamp control wire, often in the loom that flexes into the tailgate or boot lid
- Water inside the rear lamp cluster corroding the reverse bulb holder and the board tracks
- Corroded trailer socket where the reverse lamp pin is bridged to ground by dirt and moisture
- Wrong bulb or a damaged holder letting the contact touch the reflector
- Wiring crushed in the luggage compartment or behind rear trim panels
- Reverse lamp relay stuck closed or shorted internally where one is used
- Shorted reverse lamp driver in the control module
How to fix it
- Select reverse with the ignition on and check whether the module is commanding the output using live data
- Remove the rear lamp clusters and inspect the reverse bulb holders for water, corrosion and burn marks
- Disconnect the lamps and see whether the code still sets, which isolates the lamp from the wiring
- With the lamps unplugged, measure resistance between the control wire and ground; a low value proves a short to ground
- Inspect and clean the trailer socket, then disconnect it temporarily to rule it out
- Trace the harness through the tailgate flex point and the body grommets, looking for chafed insulation
- Repair the wiring, renew corroded holders, and consider the control module only when the circuit is proven clean