Hi Janet, I would just plug something in when the VW power is off and plug something in and see if it works. Then turn VW power on and plug same thing in and see if works then. That way you will know for sure.
Keeping in mind that if it works with power off there might be a risk of battery going flat. Depending on device and its power usage.
Keep Safe out there.
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Live Life On Your Terms
DOUGChief One Feather (Losing feathers with age)
TUG.......2014 Holden LT Colorado Twin Cab Ute with Canopy
DEN....... 2014 "Chief" Arrow CV (with some changes)
I think that both Dougwe, and Geeco have hit the nail on the head
In most vehicles, it is normal for any dashboard accessories, such as USB/ciggy sockets, to be off unless the ignition key is on accessories, or fully on
After saying that, I have no experience, about VW Crafter vehicles
Suggest that with the ignition key off, just plug your phone in
If there is no indication that the phone is charging, then turn the ignition key on