I have had problems with the passenger door lock not opening/closing, the passenger side mirror changing position upon locking/opening the car, the truck lock working/not working & the radio changing channels on its own. All of this (except the door lock & mirror) are intermittent.
Various Electrical Problems on 2002 Volvo S60
I suggest you have the entire computer system checked for updates. Updated software may very well address a couple of these issues, however the door lock issue is likely a bad door lock assembly. Find a Volvo shop that has the ability to update the software and have them perform a complete upgrade. A dealer will be able to do this, but some independents can too.
Thank you - will give this a try!