power problems

[hack8or]

Howdy, I've got a Flagstaff by Cobra trailer, and when I set it up this spring had the following electrical issues:

On shore power, interior lights work, water pump and furnace do not.

On battery power, _nothing_ works, but the battery is charged.

On shore power, I put a voltmeter on the pump hot lead and get 12volts, but as soon as I turn the pump on the voltage drops to zero.

If I run a wire from the batter to the pump, the pump runs fine.    

I'm guessing the reason the furnace doesn't work is it also isn't getting any power but I haven't trouble shot it yet.

Don't suppose anyone as a wiring diagram for one of these semi-oldies.

[AustinBoston]

What year is it?  You'd be surprised what people have hanging around.

Does it have a 12V converter?  I would start by checking the fuses on the converter.  Then make sure each 12V connection is secure.

Initially, it sounds like a badly corroded 12V connection, which would show 12V on an open circuit (no load), but would immediately drop to 0 when a load is applied.

Austin

[dirtracin]

A friend of mine had the same problem and it turned out to be a loose ground wire

[wavery]

Sounds like a poor ground. It will show 12v on the meter but when you put a load on it, it won't supply enough amps.......yep....bad ground (or corroded connection somewhere) would be my guess too. :sombraro:

[hack8or]

Sounds the consenus is a bad ground so I'll check that.  First I have to replace the winch since the entire socket/brake assembly fell off while I was towing.  Luckily on the way home!

[aw738]

I had a similar problem. I ended up replacing the main lead from the battery to the converter. By the way I made sure to throw the old wire away so I wouldn't use it for something elese.