how to fix left door mirror.

You don't specify what problem with the mirror you are trying to fix. Has the power mirror stopped working? Is the glass broken? Has the mirror been hit and knocked off the door? Without knowing what is wrong, it is difficult to answer this question.

I need to fix one also. I just want to completely remove and replace it. Anyone know how I do that?

if you want to replace it,you have to remove door pannel,theit will be 3 screws to remove mirror at front door post,remove them replace it.