Code
C1522
HYUNDAI
C — Chassis
Head Lamp Light Signal Line Open | Headlamp Switch Signal Line Open
Views:
UK: 16
EN: 18
RU: 10
AI status
Completed
Completed
100%
Causes
- Open or broken wire in the headlamp switch signal circuit
- Loose, corroded or disconnected connector at the switch or BCM
- Failed headlamp switch or multi-function stalk
- Blown fuse or poor fuse contact in headlamp feed circuit
- Damage from repair, aftermarket installation, or rodent chewing
- Faulty BCM or internal input circuit (less common)
Symptoms
- Headlamps fail to turn ON or OFF
- Dash headlamp indicator does not respond when switch is operated
- Automatic headlight features (if equipped) do not function
- DTC warning lamp illuminated or stored codes present
- Inconsistent or intermittent headlamp operation
What to check
- Verify battery voltage is stable before testing (12–14 V with engine running)
- Visually inspect headlamp switch, connectors, and wiring for damage or corrosion
- Check fuses related to headlamp circuits and BCM inputs
- Use a scan tool to read C1522, status, and any related freeze-frame data
- Backprobe the headlamp switch connector and BCM input connector while operating the switch
Signal parameters
- Expected OFF signal: ~0 to 0.5 V (depending on vehicle wiring; open = no continuity/high impedance)
- Expected ON signal: approx. battery voltage ~11–14 V when switch supplies +12 V
- If signal is pulled to ground by switch, expect
- Open-circuit signature: no change in voltage when operating switch or infinite resistance in continuity check
Diagnostic algorithm
- Safety: Park on level surface, key OFF, secure vehicle and wear proper PPE.
- Retrieve code(s) with a scan tool and note freeze frame/related codes. Clear codes and see if C1522 returns.
- Visually inspect switch, harness, and connectors for damage, corrosion, or aftermarket taps. Repair obvious damage.
- Check related fuses and fusible links; replace any blown fuses and re-test.
- Backprobe headlamp switch connector. Operate switch and measure voltage at the signal pin relative to chassis ground. Compare with expected signal parameters.
- If no voltage change, check continuity between switch signal pin and the BCM input pin. Expect low resistance (
- Wiggle test the wiring and connectors while observing voltage/scan tool to find intermittent faults.
- If continuity is OK and correct voltages are present at the switch, suspect BCM input fault. Verify power and ground to the BCM and check for other BCM faults.
- Repair wiring or replace the headlamp switch as required. Use solder and heat-shrink or proper crimp connectors; protect with loom and sealant.
- After repair, clear codes, confirm proper operation (switch ON/OFF, auto features), and road-test to verify the code does not reappear.
- If BCM replacement is required, follow manufacturer procedure for programming/initialization.
Likely causes
- Broken wire between headlamp switch and BCM or junction connector
- Corroded/poor pin contact at the switch connector
- Headlamp switch internal failure
- Open fuse or melted connector causing loss of signal
Fault status
Status
Stored when the headlamp switch signal line is open or out of expected range and the BCM does not detect the headlamp ON/OFF signal. May cause lamp function loss or incorrect lamp control.
Repair difficulty: Medium
Diagnostic time: 0.5-1.5 hours
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