Hi, in my trailer is a control panel with three switches. One is to turn the tank monitors and the second one is for checking the status of each tank and the batteries. The third switch is for the water pump. The water pump switch isn't marked as to which direction is on or off. [I'm old and can't remember] So this has been a guessing game for us. We don't boondock that much, but when we stop to take a break, we need to use water from the fresh water tank. When we get to our site and connect the fresh water hose, the next question is: “Did we leave the water pump on or off?” And with the water hose connected we wouldn't hear the pump running, but I still want it turned off. So, I finally added an LED [red] that lights up bright and tells us that the pump is on. An after thought was that I could have searched for a replacement switch that is lighted, but thought that it would be lighted all of the time, so I opted for the LED and I'm happy with this decision.