Code
B2565
HYUNDAI
B — Body
Left Front Fog Lamp Open
Views:
UK: 9
EN: 16
RU: 10
AI status
Completed
Completed
100%
Causes
- Burned-out/broken fog lamp bulb (filament open)
- Disconnected or loose bulb connector
- Corroded or water-damaged connector pins
- Open wiring/harness (broken conductor, chafing, connector separation)
- Blown fuse or faulty fog-lamp relay
- Faulty ground connection for the lamp circuit
Symptoms
- Left front fog lamp does not turn on
- DTC B2565 stored in BCM (left front fog lamp open)
- Possible fog lamp indicator shows only one lamp or lamp failure message
- No current drawn at left fog lamp socket when lamps are commanded on
What to check
- Visually inspect left fog lamp, lens, and mount for damage or water ingress
- Check bulb condition by removing and inspecting filament or test bulb in a known-good socket
- Inspect bulb connector for corrosion, bent pins, or loose terminals
- Check fuse(s) and fog lamp relay in the fuse/relay box
- With the fog lamp command ON, measure voltage at the lamp socket (pin-to-ground)
- Measure continuity/resistance between the lamp connector and the BCM/fuse box; wiggle harness while observing behavior
Signal parameters
- BCM fog lamp command (ON/OFF) — logical state from scan tool
- Socket voltage when commanded ON — approx. battery voltage (~11–14 V) if circuit intact
- Resistance/continuity from lamp socket to BCM/fuse — should be low (ohms)
- Current draw when lamp is ON — halogen fog bulbs typically ~3–5 A; LEDs much lower
- Ground continuity to chassis ground — near 0 ohms
- Presence/absence of related fuse/relay voltage feed
Diagnostic algorithm
- Confirm customer complaint and retrieve/record DTC B2565 and any freeze-frame or related codes
- Visually inspect left fog lamp assembly, connector, and wiring for damage or corrosion
- Remove the bulb and inspect filament; if doubtful, test the bulb on the right fog lamp socket or a bench power source
- With the fog lights commanded ON, measure voltage at the left lamp socket pin(s). If battery voltage is present, suspect the bulb or ground; if no voltage, continue diagnostics upstream
- Check continuity between the lamp socket and the fuse/relay and between the socket ground and chassis ground. Repair any open connections or corroded terminals
- Verify fuse(s) and fog lamp relay operation. Replace if faulty and re-test
- If wiring, connectors and fuses/relays are good but no command signal, use a scan tool to command the lamp and monitor BCM output. If BCM does not command while inputs are correct, consider BCM driver fault and inspect BCM grounds and connectors
- After repairs, clear codes, cycle the fog lamps and recheck. If code returns, capture freeze-frame and perform further BCM-level diagnostics or consult manufacturer repair procedures
Likely causes
- Bulb filament failure
- Loose/disconnected or corroded bulb socket/connector
- Open wiring between bulb and BCM or fuse/relay
- Blown fuse or failed relay
- BCM output/driver fault (less common)
Fault status
Status
Left front fog lamp circuit open — no continuity detected; left fog lamp will not illuminate. DTC stored by BCM.
Repair difficulty: Medium
Diagnostic time: 0.5-1.5 hours
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