semiatic

Door open light

A door, the boot or tailgate, or the bonnet is not fully closed. The symbol is usually the car seen from above with the open part drawn out of line.

Red

Not defined by regulation: a maker convention

What to do

Stop where you can do so safely and close the door, boot or bonnet properly until it latches. If the light stays on with everything shut, a latch switch may be faulty: have it checked.

Makes differ: what this light means on your car, the other colours it may use for the symbol and what the car wants you to do are set by the manufacturer, so your car's owner's manual is the authority.

Symbol
Car seen from above with a door open
Colour
Red
Standard
None — a maker convention, described here from 3 makers: Volkswagen, Kia, Hyundai

Where makes differ

Volkswagen has separate red lamps for the doors, the bonnet and the boot lid. Kia uses a red door-ajar light plus a separate tailgate-open light. Hyundai's single door-open indicator covers every door and the liftgate.

Not defined by regulation: a maker convention

Neither US FMVSS 101 (Tables 1 and 2) nor UN Regulation No. 121 lists this light, so no rule fixes its symbol or its colour. What follows is what the makers cited below say; other makes, and other model years of the same make, may draw it differently.

Neither FMVSS 101 nor UN R121 lists a door or bonnet tell-tale.

Other red maker lights

All red dashboard lights, regulated ones included

Sources

No regulation defines this light, so it is described from 3 carmakers' own manuals or owner pages, each fetched and checked on the date shown:

Written in our own words; the makers' pages cover their own models only.