In my 97 Bounder, there are 3 places where I can turn on or off the pump. It is a momentary switch at each location, and if the pump is on, it will turn it off, or if off, it will turn it on.
Any switch will change it from off to on or on to off.
I have a switch in the kitchen, one in the bathroom and one in the sewer clean out area. Each has a light, that has long ago burned out and when the RV was new, the light would come on when the pump was 'on' position.
There is a relay feeding power to the pump located near my pump. It has a 12 volt DC inlet, and a wire going someplace, I guess to the three switches. It also has 12 volt going to the pump when the light is on and the pump should have power.
I suspect that this relay went bad, and you need a new one. But I may be wrong, (typically I am pretty good though).
You also need a new RV service facility, as the one you where at just seemed to 'hot wire' the pump, and feed it 12 volt power all the time. While this may 'work' and get you out the door, it is not a good solution. Say your tank starts to go empty, and the pump is energized. The pump would not shut off if it has drawn in water and will not pressurize to 55 PSI (like it has been doing while this problem has happened.).
For now, I would recommend pulling off the feed wire or fuse to the pump, so it will not run when dry (the fresh water tank has no water, if the pump has 12 volt power to it, the pump will be damaged.).
Good luck, hope you find a good mechanic!
Fred.
