Question about switch in head

[ccruser1]

Greetings Captains,
As a recent new owner of a 2300SCR I would like to know what the red toggle switch in head is for. I believe the label says shower but the water pump switch is located on the counter in the galley next to the fridge. Turning the switch in head on or off does not seem to make any difference in the operation of the shower.
The Maxum manual does not give any indication of what this switch is for.

Thanks,
CCRUSER