Once we got the chair off of the pedestal (four bolts) and turned it upside down we found a connection that was loose. The connection was a cable that looked very similar to a speedometer connection. It had apparently vibrated loose; but you could not see it until the chair on its side. There are two of these, one for each side of the leg lift. One side had come undone but the other was still connected. They run from a small motor to the screw drive that operates the leg lift on each side.
Screwed it back in and the leg lift works fine!! It you try this, two important things to know. First, unbolt the chair from the top of the pedestal, not the floor. Second, there is another cable that controls the release of the chair so it can swivel. You have to take it loose and need to make sure you remember where it connects!! There are two points relative close to each other that the little "L" bracket that holds the cable can connect to. We got the wrong one on the first try and the swivel wouldn't release. Checked the other chair and realized our error.
It takes two people to perform this task as the chair is rather heavy and getting it back into position takes one person lifting and the other person guiding it so the bolts match up.
I love it when something is actually much easier to fix than you feared....