Sounds like one of the door switches (located in the door jamb of the doors) is faulty. Either the switch contact is not opening when the door is shut or the switch is corroded and there is a permanent earth signal on the signal lead back to the body control module or the instrument panel (depends on model and year).
There are plenty of videos on YouTube that show how to check if the door switch is OK
+
+
=== Update (03/16/23) ===
+
Hi @kent29659
+
+
Couldn't find a video for your exact vehicle, but here's a [link|https://www.youtube.com/watch?v=3UjYPjY0IXw|video] that shows what to look for. The principle of operation for the door ajar light is the same for most vehicles. What can differ is the location of the switch and its design etc.
+
+
This is what the [link|https://www.ebay.co.uk/itm/165371482434?fits=Car+Make%3AVauxhall%7CCars+Year%3A2005%7CModel%3AAstra&hash=item2680e89142:g:EvwAAOSwx-9iJbfc&amdata=enc%3AAQAHAAABAHevdBYBJwKTF8NX%2FIos8a2VGJ5D1UsbrcetZDCnVsUAEtQUHLZCQn9QefmhjUbcU0HTdpSdjL5xfkrW8E7Txog25%2FdqbctY9H8rxtNmLou6%2BYHBPfNMMuyhA8nNnWeRcE5%2FWChAcJ8ngTQCfmJLTxFRP67NE6crg9v12DRetZ3cYhWmiM6m1y6mIQ8WIQdmV1ry14R9NuZmdfpkE9kx6QhCftUvy6tP%2Blu8mprfvDH8UIa%2FiBHux7ka%2Bp%2F9o1Hpg2qU%2FzRhSifBVKEFh8WEenMffk9LAfEFLxTMP4P%2FOwd4gj%2FLewpkA2AtYTCuHM9jAGbWFrcvwkRClFkpexw2kv4%3D%7Ctkp%3ABFBM8Nroqd1h|switch] looks like for your model. (supplier example only, there are others online that may suit you better). The trick is to find out which one of the 4 (one for each door) is the problem and hopefully it is not a wiring problem
Hi @kent29659
What is the year and model of the vehicle?
Sounds like one of the door switches (located in the door jamb of the doors) is faulty. Either the switch contact is not opening when the door is shut or the switch is corroded and there is a permanent earth signal on the signal lead back to the body control module or the instrument panel (depends on model and year).
There are plenty of videos on YouTube that show how to check if the door switch is OK