What does it mean?
B1659 is a Body (airbags, seat belts, body electronics) fault code. It indicates: Front Fog Lamp Control Circuit Low .
Symptoms
- Front fog lamps do not switch on, or only one of them lights
- Fog lamp fuse blows repeatedly
- Fog lamp indicator in the cluster lights up although the lamps stay dark
- The lamps flicker or glow weakly, especially in wet weather
- The circuit shuts down after a few seconds of operation
Likely causes
- Short to ground in the fog lamp control wire, often where the loom runs behind the bumper or along the wheel arch liner
- Water, salt and road grit inside the fog lamp connector or the lamp housing
- Cracked fog lamp lens letting moisture reach the bulb contacts
- Stone or kerb damage to the lamp and its pigtail after low speed impact
- Aftermarket high wattage fog bulbs or auxiliary lights added to the same circuit
- Stuck or internally shorted fog lamp relay
- Shorted fog lamp driver inside the lighting control module
How to fix it
- Check the fog lamp fuse and confirm with live data whether the module is actually commanding the output on
- Inspect both fog lamps for cracked lenses, water inside the housing and corroded connectors
- Unplug both fog lamps and see whether the code still returns, which separates the lamps from the wiring
- With the lamps disconnected, measure the resistance between the control wire and ground; a low value proves a short to ground
- Follow the harness behind the bumper and along the wheel arch, looking for chafed or crushed insulation
- Remove any auxiliary lighting or non standard bulbs added to this circuit and refit the specified type
- Repair the wiring with sealed joints, replace a damaged lamp assembly, and only then consider the control module