Why do i not have interior lights or my water pump quit working

Must have a lot of new member squirrel moments going on here. 
Just like the OP here who posted a completely vague question only related to something that has nothing to do with power to camper. 
And only to not return. Mustn’t be an issue or they realized someone unplugged the camper while they were distracted replacing the flooring, lol!

Agreed we probably need more information on what you did before it stopped working. Like were any of the batteries disconnected and then reconnected? 

Are you plugged in to shore power?

Look for a master battery disconnect possibly just inside the entry door.

The reverse polarity fuses might be blown. These fuses sometimes are behind the fuse panel where you can't get to them. If you can find a name and possibly model number of the fuse panel we can probably look it up for you.

I kind of avoided this one yesterday as it is lacking so much information and is going to get a shotgun of answers.  

so basic questions

1, is it plugged in?

2, is the battery in place, is it dead, what is the voltage? 

3, how old is the rv and what is it?

4, do you know the model number of the power center?  

as listed below with the description we have it could be the converter, some real old rv's did need a battery for 12V but not many, but the question about the battery voltage is to determine if it is charging or not, if you are plugged in.  a fuse is not likely as newer rv's will have the water pump on a different fuse from the lights, that's why age of the rv helps.

so if I were to guess now, I would say it isn't plugged in and your battery is dead.

if you told me it was plugged in, I would ask if the outlet it is plugged into is tripped, if it is good and you have power for 120V stuff in the rv, as in the outlets will work with a light or something then I would say check the breaker for the converter and if it is fin, your converter has probably gone and your battery is dead.  

You lost 12V power. Dead batteries, inverter, battery shutoff switch/solenoid. Lots of things could cause it. 

Your lights, for the most part, are 12 volt and so is your water pump. So it sounds like you definitely have an issue with your 12 volt system. Sounds like Your converter, that charges your battery and supplies 12 volts to the system, has quit. Might need replacing. Your Trailer battery would likely be dead at this point because of it as well.

EVen if plugged in you need a good battery for 12v stuff to work.

Is the battery dead? Do you have the unit plugged in to a 120v receptacle? Could be lots of things, but the simple thing is to check the power source(s) first.