what edwardt says is a reasonable assumption
if the contactors are chattering when the function(s) are actuated is a sign of a weak battery for sure.
At this point though it could be many things, the tech did go in and remove the steering card and inadvertantly may have connected something back wrong, the steering card may have not been repaired correctly, they may have sent back the wrong card, just too may variables to consider, especially being that there is a whole new set of problems that arrose after he put it back together.
And of course the dealers response is pretty much a normal response if they donot have anyone in the field that has the knowledge required to do this job. Sure, they take it back to the shop and let the shop electric tech probe through the lift and find the issue and repair it. But mind you, at the point that their tech screwed it up is "thier expense" not yours. All you are required to pay for is the intital repair which would be the steering failure which would include the componet that caused THAT failure. Any other damage THEY would be required to absorb that cost if it is in relation to the tech's incorrect actions. And if the lift was running ok except for the steering code to start with then anything that has arrisen after the fact would indeed be his error.
Just keep this in mind IF you allow them to take the lift in.