Check both ends of the cross shaft that connects the 2 leg gears. If the bolt came out, then the DS leg wont raise. Sometimes the bolt and nut are there. The bolt and nut might be laying on the floor of the compartment. It does happen.
Bob
That happened to us. If the jack raises part of the way then it may just need realigning (cross your fingers on that!). Try removing the screw that holds the cross shaft together near the leg that needs to come up. You should then be able to raise the leg up manually (you'll need the trailer on your Tow Vehicle to do this). Raise the leg until both legs are at the same height. Then reattach the cross shaft bolt. Try running the legs up and down a few times to see how it works (keep the trailer hooked to the Tow Vehicle while doing this!). If you're lucky, the problem will be corrected. If not, you can get the parts to repair it from Lippert or Venture (the jack manufacturer) and do it yourself (cost me $25 and two hours labor) or you can take it to any RV dealer for repair.
the sundance is at ron potts rv being fixed under warrenty as i post