Sounds like you have a flaky connection, so check that first. Unplug the head of the leg, make sure the contacts aren't corroded, then spray them with "light bulb grease", available at radio shack or marine stores.
The connections for all 4 legs run to a control module. Mine is under the dash, mounted to the driver's side wall and firewall. You'll see 4 pairs of heavy gauge wires connecting to the module. Make sure those are clean and seated properly as well. It's actually a terrible location, because if you get any condensation on the driver's side window, it can run down the wall and land right on the connections, at least in my case.
If it's still acting funny, you may need to do a reset.
I don't recall the steps off the top of my head, but Atwood tech support has always been pretty good when I've called them, and I think the reset steps are in their documentation in the back under Troubleshooting.
Good luck,
Jim
