Planning the next
AO Silver Member
Join Date: May 2007
Location: United Kingdom
First thing to do is disconnect and reconnect the connector between the door and A pillar in case there's a poor contact in there.
If that doesn't fix it, there are two possibilities that come straight to mind.
1. the microswitch cam needs readjusting and tightening
2. the microswitch is in the process of failing.
Both those will require the removal of the door card.
For 1. It's a free fix. Just adjust the cam until you get the correct amount of drop with the door open and tighten it back up.
If the microswitch has failed, you can get replacements for about £60 from Alfa. Or, you can buy the same microswitch for about £15 elsewhere and crimp on some terminals.