Actually, that "should" be a relatively easy fix, at least on a trailer. You would have to lower the underbelly, and figure out which cable is causing the problem. Trace it back to the valve on the tank, the cable is attached to the valve by a set screw. First you could try pushing the valve to the closed position to see if enough of the cable comes out. If not, loosen the set screw, then push the cable to the closed position. Also, there are 2 nuts on the cable near the handle, one on the outside near the pull handle, and one on the other side of the wall, loosen the 2 nuts, and the cable & housing should be able to be pulled out.
