120 power not working the water pump or landing gear

Landing gear and water pump are 12VDC. So it appears you have a battery problem. Start gy having the battery load tested and move on from there.

Water pump runs on 12 volt DC which is derived from your battery bank, or from your rig's onboard converter which converts 120 volt AC power into 12 volt DC power. Battery power should always be switched on while RV is in use if you have a battery disconnect switch, sure you can turn it off while plugged into power pedestal as 12 volt DC powered items will continue to work if your converter is functioning and properly wired to DC distribution center, although your battery bank will not recharge which is one of the primary functions of your onboard converter. From your description it sounds like something may be amiss with your converter although no voltage measurements were given.

Dont turn the 12V off - ever.

ScottG wrote:
Dont turn the 12V off - ever.

Except when put in storage and you don't want a dead battery when you return...

But yeah, when using the RV, leave it on.

Battery disconnect is for when you STORE the RV and are not using it and it is not plugged in
When camping leave the batteries on, the batteries work all the systems in the RV including the fridge controls
And the converter charges the batteries
Only use the battery disconnect when Storing the RV with out being plugged in
When camping with or without shore power you must leave the batteries connected for things in the camper to work
Things should work from battery when you unplug from shore power
But they can't work if the batteries are allowed to go down, because you keep disconnecting them so they can't be charged
Have your batteries 'Load' tested at an auto parts store
They may not be any good

I am new at this but have been out about a dozen times and have only turned the I had the battery shutoff on once when no shore power available. The rest of the time I have kept the main battery shutoff on off. The batteries have stayed charged. I have shore power to it all the time in storage, but have kept the battery shutoff on off. This last trip the landing gear and slides only wanted to work with the battery on. Shore Power alone did not want to make the landing gear work.
Thanks Guys. You gave me some ideas that I will look into when I get home.

The converter expects a battery to be connected to stabilize the output. It may have a safety shutoff when it senses an overvoltage condition, which can easily happen if loads are turned on/off with the battery disconnected.

Worst case, since the behavior has changed, is that the converter is now damaged by running it without a battery connected. Leave the battery connected except when in long term storage and not plugged into AC.

Well, some accurate info and some not so good.

First, yes you need 12v to run the water pump and landing gear.

Second, do you need to have the batteries on when connected to shore power? That depends on the converter. Some need a battery connected and some don't. Ours doesn't need a nattery connected to supply 12v for the water pump, lights, etc.

Third, always leave the batteries on when connected to shore power. That depends as well. Does your converter need a battery connected to function properly? Is your converter a smart multi-stage converter? A dump converter can over charge and boil the batteries if they're on and connected to shore power for an extended period.

Are things working as they should? You need to find out what type of converter you have then go from there.