Windows - openning all the way whilst driving

[Chrisp]

Has anyone encountered this?

Whilst driving along, intermittently both windows will open fully, and the interior lights come on. The windows drop down completely - so it's not the hood micro switch.

Car has been out in the rain, and the interior is steaming up a lot, but I'm not sure where to start if it's water damage... I've looked at the ignition switch threads and none of them describe this as a symptom and the key feels fine.

Any thoughts would be helpful - my partner took it out the other day and nearly lost a load of helium balloons because of it!

Thanks to all.