Hyundai Fault Code
Free · no signupB1504
Auto-Headlamps Stays On in Daylight
System
Lighting / Lighting Control
Symptom
Auto-Headlamps Stays On in Daylight
Diagnosis & fix steps
LOGIC: Rain / Light Autolight Sensor Circuit Open Input.
ACTION: Inspect upper windshield glass layout right around the rearview mirror base trim cover. Clean heavy smudge films off glass face over top of the sensing eyes.
Red Seal field insights
Optical Blindness: An open signal line pulls up reference voltage limits, tricking smart lighting modules into assuming absolute dark, forcing headlamps on.
Same code keeps coming back?
That's a program problem, not a part problem. Book a 30-minute uptime review with Grant, a Red Seal Heavy Duty Technician.
Read before you touch anything
- This is general reference information, not a repair manual. It is for trained, qualified technicians.
- Fault codes, meanings and procedures vary by model, serial number and software version. Confirm the code and the procedure against the manufacturer's service manual before acting.
- Follow the OEM service manual, torque specs and your site's safety procedures: lockout/tagout, block raised equipment, relieve hydraulic, fuel and air pressure, and let hot systems cool.
- You use this information at your own risk. Adventure Mechanical and AM Fleet Integrity accept no liability for damage, injury, downtime or loss arising from its use.
- Not affiliated with or endorsed by any manufacturer. Brand names are used only to identify the equipment a code applies to.
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