300te side view mirror...
 

1989 300te. The drivers side view mirror is peeling. The inner case (aluminum) needs to be stripped and painted. So, I took off the whole assembly...to reveal that there are wires to the housing. I assume defroster wires (manual adjustment, so no motor). How do I determine if the mirror glass is hooked up? Any way to get to the back of the mirror? Remove the mirror? I see that the outside case of the mirror housing is plastic...can that be removed? Or is this thing a solid, no-take-apart unit?
AND...how does the defroster work? How do I even check if current is going to the mirror?

Glass just pries off.

Kind of a ball-and-socket mount.

The side mirror defrosters work together with the rear window defroster. In some models it works automatically when humidity is detected at the mirror.

So, how do I check if the system is working? In my hand is the mirror, disconnected from the housing. The car has a connector that the mirror assembly plugs into. Would a 12 volt light be useful? Or an ammeter?