Diagnosis
The safety tip-over switch or overheat thermal protector tripped. This happens if the heater was knocked over, placed too close to curtains/furniture, or the vents were blocked.
How to Fix It
Unplug it, let it cool down for at least 30 minutes in a well-ventilated area. Ensure it's upright on a hard, flat surface with at least 3 feet of clearance on all sides, especially the front and rear. Plug it back in. It should reset.
If That Didn't Work
If the light remains on or it instantly trips again when cool, the internal temperature sensor might be faulty or the motor fan might have failed, causing overheating even when vents are clear.
Heads Up
This is a critical safety feature. Never attempt to disable it. If it trips repeatedly under normal use, the unit has an internal fault—stop using it.