How do i replace a broken driver side mirror on a 2010 mitsubishi galant?

not exactly same steps but similar. Most cars I have worked on the screws were along the bottom and on the arm rest. Make sure you remove all screws some may be under a access panel. Use caution when pulling on clips

REPLACE MIRROR

Not really.

1. Remove the plastic mirror cover (on the inside of the door) and this will reveal the mounting screws and wiring of the mirror assembly.

2. Disconnect the mirror wiring loom on the inside of the door

3. Remove the screws and withdraw the mirror assembly from the door.

Here's a good video on how to do it:
https://youtu.be/dk_sZNy55o8

mcdevito75 here, This is a shop job as part or all of the door panel has to come apart. Check out an auto glass replacement shop in your area.

From inside car, remove plastic mirror plate, then remove the 3 screws that hold on mirror.

On the inside trim, you can remove screws that are by the door handle, arm rest, under door and side of door and then gently pull back on the panel as there will also be retaining clips attached and you don't want to break them. You'll need to lift the door panel upwards in order to get it off the window ledge. Then you'll need to manipulate the panel and disconnect the door handle linkage from the door handle and disconnect the wiring for your controls. Then you can access the bolts that secure the mirror onto the door

My mirror got knocked off by a deer running into the side of my car.

I mixed up some five minute epoxy and put it into the male and female joints that connect the mirror to the car. Hold it on tight without movement, for ten minutes and you are done.

you need to remove the door panel ,to install mirror assy-tere are no special tools(10mm socket,ratchet and #2 phillips screwdriver)3 nuts hold the assy. to the door and the connector is easy to see,there are no special sealers needed(seal is already on mirror assy)good luck!

Patch it if you can, If not try to find one on Ebay It is easy to change the hard part might be getting the door panel off if it needs to come off.