Frage Glovebox USB

I have found that there is no power to the glovebox USB socket, whereas all the other van USB ports are powered. This is preventing a firmware update to the Kenwood sat nav using  a USB stick. Any ideas why no power to the glovebox USB?

Hi,
usually the USB socket works when the engine is running, did you try?
Regards, Michaela

Hi Michaela,
Thanks for your reply. Yes, I tried it with the engine running. 
Kind Regards,
Michael