Always a puzzler when the gremlins pop up their little troublesome heads!
So we need to troubleshoot the problem a bit I think. Plug the v1 into the lighter to eliminate the unit itself from the list of potential problems.
If the v1 comes on, and you said the sunroof works, then the problem is with the wiring.
I forget, is there a separate fuse you can check when you install the v1 like this?
If there is, then check it. If it's fine or if there isn't a fuse to check (we know the sunroof works) then the problem is in the wires themselves. In which case you can rewire it.