Dome light on if your a3 thinks that the door is ajar it ll leave the dome light on.
Audi door open sensor.
This can create some visibility.
The sensor typically uses a switch with a spring loaded plunger that is compressed when the door is closed and is released when the door is open.
On this occassion all door handles and boot sensors work when unlocking the car and all locking sensors work except on on drivers door.
If the garage door opener closes the door with the safety sensors blocked replace the logic board.
Here are the most common symptoms when the door jamb switch has failed or the door ajar warning stays on.
The door ajar warning staying on is usually caused by a bad door jamb switch.
Attempt to close the garage door using a remote.
Place a box or similar object between the safety sensors to block the sensing beam.
Open the garage door.
The door should stay open and the motor unit lights should blink.
This article applies to the audi a6 c5 1998 2004.