Tank Monitor and Battery Level Panel Not Working

Make sure the battery is not connected backwards.

Believe it or not Home Depot and Lowe's have an amazing variety of switches including toggle and rocker. It's pretty handy carrying in the old switch then staring and comparing at possible replacements.

Probably not Radio Shack since they have gone or are in the process of going out of business—though if you do get lucky at one, you might be able to get the switch really cheaply.

Typically these are snap-in switches (as in you slide them into their holes and there are tabs on the back that spring out to hold them in place). If you remove it from the mounting and measure the hole dimensions, you have the information you need to find a momentary toggle switch somewhere.

Mouser and DigiKey are two large and reputable supply places that have many many switches available and will sell to individuals in small quantities. You should be able to find something that's the right size and style and (approximate) color.

I found it. I got my multimeter out verified that 12V was getting to the test switch. I then touched the two wires together and the lights work. So, now I need to find a place to buy a new test switch. I'm guessing maybe Radio Shack or somewhere.

You need a 12-volt test light and an inexpensive digital handheld meter to help you with minor issues like this. The alternative is to substitute via purchase or pay a hundred dollars an hour for someone else to do the same thing. But guesswork is expensive, and frustrating. Many times there are zero easy ways to test something by process of elimination using guesswork. Your panel lost supply power. Is it a fuse? Is it a burned out power supply? is it a positive or negative power feed break? The working water pump switch proves there is 12 volt power nearby. After that conclusion it's all guesswork without a meter and test light.

I did notice last night that one fuse is missing in the fuse box. It says it's for the LP sensor but maybe the tank monitor panel runs through that fuse as well. I know that those monitors aren't really accurate most of the time but I would at least like it to work. I'll try adding that fuse and see if that works. Thanks.

Could be a ground wire for the panel. Water Pump switch would just close and open the hot wire.

You can replace the switch for the pump. Obviously power is getting to it or the pump wouldn't come on. It's just not lighting up

You can pull the monitor panel & check connections there also, but it too probably needs replacing. Having said that, the monitor is not reliable anyhow. It can only read what the sensors say for the tanks & they may not be working any longer. I believe most of us don't rely upon the panel to be accurate, especially for the battery. DON'T rely on the monitor for the battery. Best to get a hand held multimeter to check voltage, or install a meter inside the coach for that purpose.