Have a red switch in the bathroom to the right of the sink just below the light switch. I’ve had this coach six years. Never thought it did anything. But. When the water pump is running and I flip it, the tone changes. So it apparently does something…
I have no idea what tho.
Any ideas.
92 breakaway.

Howdy Bob
We have a red switch in the bedroom . I found out by mistake that it went to the water heater .
I suppose they wanted to heat the water before getting out of bed . It turned on the propane function on the water heater .

I have a '92 Breakaway with a water heater merely propane. I do not have such a "red switch". I suspect you may have a two-way water heater - propane and 120V. When the switch is activated and the water pump sound changes are you plugged into shore power? And no sound difference when not plugged into shore power, rather using your 12 volt domestic? If so it is probably a 120 volt source to the water heater.

I saw your question on Facebook before I saw it here. Tank pad heaters. That is why the change in sound. Draw from the pads. Answering here to benefit those finding this post. Might help them.

If the switch activates tank heat pads you would think the circuit would have an ambient temperature interrupter. I doubt you'll be using the system in Louisiana.

You possibly can get information from the 120 volt breaker panel at the foot of the bed. Turn on the red switch, activate the water pump and flip the individual breakers while listening a change in pump's sound. Please update.

You have confused me and Bob .

Bob lives waaayyy up north

Our red switch in the bedroom turns on the water heater .

Bob's red switch is still a mystery .

Sure did.
A water heater red switch would not have an ambient temperature cut out. If the switch draws on a warm day it's more likely to be to the water heater. The answer lies in the breaker box at the foot of bed.