To remove the caps you must remove the glass,
start with some tape put it on the bottom below the mirror then with a flash light you will see where the mirror attaches (look up from the bottom of the mirror)and slowly pry it off it will pop off don't worry about it,then dis connect the 2 wires(it doesn't matter which way you plug them back in),then with the flashlight look into the mirror housing you will see about 4 tabs just disconnect them and the cap will fall off.
**NOTE** do not reinstall the glass before you put the cap back on b/c you may install the cap and there maybe a problem you can easily pop it back off b/c the glass is not in it.
Hope this helps you a little bit
Frank