Mirror glass loose, but not loose.

My outdoor mirror glass is somehow loose. It sits indissolubly firmly in the mirror, but wobbles in all directions, especially on the highway by wind pressure the glass always adjusts. Adjust ( automatically by mini joystick) the mirror can only be adjusted in three directions: up, down and away from the car (so the view away from the car) The motor works towards the car, but the glass does not move. I always stuff a small piece of wood (stock, splitter whatever… ) between is a) very annoying and b) dangerous on the highway… Can I do something or how do I take out the mirror glass and look at the adjusting unit? (is a heatable mirror by the way)