1990 4 runner - Q- My side rear view door mirrors are loose and was wondering the
best way to remove them to access the three little phillop head screws that
are frozen. Inside the door there is a piece of triangled plastic - Do you take these off
to get to the mounting bolts ?

 

tap or stick a flat driver into the triangle to pop it out. careful not to snap anything. before that i would inspect all around for any screw holes. check the gap behind the mirror.