"Sie bewegen ihn links."
Yeah, you're right. Could you elaborate on what this sentence is supposed to mean, then? I really don't get it.
This sentence is so out of context, you can hardly tell more than the literal translation plus some fantasy. 'Sie bewegen' is either a formal you or a plural you, meaning that some speaker seems to give order to someone or describes what is happening in this situation to someone else. Pretty much, it sounds like two or more people want to move something, probably big or heavy or fragile, hence their number. I can't help myself but think of a whale, maybe a body being moved for some reason. In any way, this sentence is rather incomplete all by itself. There must be context, else it would make not much sense at all.
The above deactivated user names it, here are lots of sentences, which have or make no sense without context and some are even wrong. Don't bother too much in such cases, I am native German speaker and I would agree to what was said above: move to the left is in German "nach links (hin) bewegen". Links bewegen means it/he moves on its left hand side only maybe a body part or something, if it is something rigid it wouldnt work anyway, because if you move it on the LHS the whole thing moves. If they want to say they move it from the left, making use of a handle/grip mounted on the left, it would be in German: "Sie bewegen ihn von links" or "von der linken Seite" Hope that helped a little. :-)