Steam box in shower gushing water

[doppy]

We have a monstrosity of a shower which has all these unnecessary features, like jets and steam. The steamer hasn't worked in years, but recently the little steam box at the bottom of the shower has started gushing water when the power is turned on. I don't need the steam to work, but I would like to stop the running water as I'm sure it's leaking into the back of the shower as well. Is this an electrical fault with the shower system? If I just closed off the pipe leading to this steam box would that work, or would it cause some kind of pressure to build up?

Video: WhatsApp Video 2020-02-11 at 18.06.38 - Streamable - https://streamable.com/7eq9r