It sounds like, you have checked; some of the common power issues in the doors. Just as a reminder, of what we typically see; when a door goes dead: the wiring harness, from the body to the door (flex) portion, will eventually break the wires, killing power to the door. On the older cars, many times; people, will install USED parts, from a different year New Beetle and these parts can fit BUT they are typically different, some even have different pinouts, on the parts themselves. These tend to be: window motors, comfort control modules, wiring harnesses, etc. So, you may not know, the history of the car, be sure to check the part #'s; see, if they are compatible with your year New Beetle and then, there are classic tell tale signs, of used parts, being purchased from a junk yard and the yellow paint marker, markings to identify them for their warranty returns.
If you have a VW specific scan tool; like VCDS by Ross Tech, you can do output testing and view live data, that will tell you the bus status, whether "up or down". The bus will go down; if there is a defective part or the part installed, is incompatible. A full "autoscan", is always the first thing to do; bad electrical parts or bus communication errors; will typically, throw a VW factory trouble code and this, can be a good clue, as to where to start your diagnostic process.
A quick way to check for the bus going down, from a bad or incorrect part; is to do a "hard reset" of the ecu, remove the pos/neg battery cables, touch them together and reinstall on the battery. Many times, this will temporarily, restore functionality to the components in the door and then, in a little while, the bus will go down again, killing the door. If this works temporarily; then, some part, is bringing the bus down and so, detective work, would need to be done, moving forward. I would confirm, the parts are correct; by researching their part #'s (confirm with ETKA or VW's parts site) and then, a process of elimination.
The Ross Tech videos; on VW bus systems, can be helpful, as well:
A good wiring diagram; is always helpful as well, the VW factory versions, can be a bit confusing, compared to the simple versions, which can be accessed from a Haynes manual, online sources like AllData or Mitchell1.
Here are some videos from Ross Tech on reading VW wiring diagrams; the might be helpful as well.
Do you have a VW factory service manual? The eRWin versions, tend to be the best and are geared towards the VW tech at the dealerships. eRWin, can be accessed; through a 24 hour subscription and then, you can download as many manuals as you want.
Otherwise, you might see; if there are some free ones, that are for your particular year and model New Beetle.
Volkswagen Workshop, Owners, Service or Repair Manuals. Free. No Ads.
www.onlymanuals.com
Here are some online versions:
Workshop Repair and Service Manuals volkswagen All Models Free Online
workshop-manuals.com
So, check things, try the ecu hard reset and review possible issues, like bad or incorrect parts. Report back your diagnostic results, research and visual inspections, we can go from there. Thanks.
