Unless the cogs are jammed you should be able to push the butler back in manually. If you're lucky it's just overshot the position microswitch and it'll come back to life.
If not, they are primarily activated by one of the door switches. Easy enough to pop out and test with a meter or check for a faint audible click from the convenience relay (under the fuse box) or the convenience module (under the rear passenger seat) when you push the switch in.
Then there's the switch in the seatbelt buckle which tells the butler to retract. They have been known to stop working or the connector for them under your seat might have come adrift. Again, easy enough to test with a meter or bridge the contacts for test purposes.
After that, I'd be looking at the butler control units, one on each side. Unfortunately the side trims have to come off for access but once in there it'll be easy enough to swap the one from the working side to the duff one.
By the time you've done all that you should know a bit more. The motors rarely fail but that doesn't mean yours hasn't.
Good luck and let us know how you get on.
