power

On later model RVs, the 12v system is running off the battery all the time, whether you are plugged in or not. The converter just charges the battery and kicks in more 12v power if/when needed.

In the older RVs, the 12v system is running off the converter only when plugged in. It doesn't get any help from the battery until the shore power is unplugged, at which time a transfer switch connects the battery into the circuit. If this transfer switch sticks in the shore power position, you will not have any 12v power when unplugged, even if the battery is full charged.
It sounds like this could be your problem.

You have done some good work on narrowing down the problem to bats, converter or relays in the system.

Have you got a volt meter that does 120 & 12v? Have you done as the 3rd poster stated and checked input to the converter and if that is good, the output? Post the results.

At the risk of repeating what enblethen said, the converter is what converts the 120vac power to 12vdc to power most of the things in the RV and to charge the battery. It sounds like either the converter is bad or the wiring and fuses associated with it have a problem.

If you have a multimeter check the ac voltage coming into the converter and the dc voltage coming out.

The converter is probably near the power distribution panel.

i have reworked all the ground wires, hooked up battery charger to the cables for the battery all works, disconnect charger and 12volt quits. Convertor????

There are a number of suspects... Now, on most MODERN RV's there is a device called a converter, it has two jobs, both of which involve converting 120 vac shore power into 12 volts DC "Battery" power or something close to that. (13.6?)

NOTE: some very small low end or older trailers may not have this device.

If you have one, faulty or.. Breaker tripped feeding it or... Mine unplugs.

Next we have teh battery itself, clearly dead or missing

Finally we may have a disconnect switch, or two turned off.

And last: The Kojac suspects,, Broken wires, bad connections and that kind of thing. (You tear your heir out till folks nickname you KOJAC before you find it)

I have had the camper on a lake lot for 5 years, never had a battery in the unit, however i put one in it and the 12 volts lights worked,I tried to run the ac at it killed the lights, before i lost my 12v supply every now and again my trailer running lights would come as if i had it hooked up to my truck.

Battery

You need to check for 120 volts to the converter. This unit changes 120 volts to 12 volts DC.
Next check the output of the converter to the 12 volt DC panel. There could be one or two main fuses.
If it is a newer Prowler, there could be reverse polarity fuses on the DC end of the converter. They could have blown if battery was connected wrong even for an instant.
The converter charges the battery in some way. There could be a fuse or 12 volt circuit breaker adjacent to the battery. If no battery is installed insure that the positive lead is insulated from ground.
Be helpful to know what converter you have. Please post.
Year of your Prowler would be beneficial.

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