Replacing the Mirror Light - driver's door

I'd call a GMC dealer and ask for the parts department. I'd ask about the availability and price of the driver's mirror turn signal bulb. That might tell you if that bulb is replaceable. You could also ask that same delaership's service department about the labor cost to replace the bulb.
If the plastic cover below the mirror will not snap off, you would probably have to remove the mirror from the door and take it apart to replace the bulb. Depending on the friendliness of the GMC service or parts department , they might tell you what to do here.

The following is from 2002 Honda Odyssey factory manual page 20-70: Driver's switch panel removal. (This is the switch panel to the left of the steering wheel with TCS, cruise control, mirror, and sliding door switches.) Gently pull on the driver's switch panel bottom right corner to release the (2) right side clips, then detach the remaining (2) clips on the left side and the single top center clip. If equipped, disconnect the cruise control main switch connector, TCS switch connector, power mirror switch connector, and power sliding door connector, then remove the panel. Once the panel is removed, you can push out the switch from the rear. The switch has two bulbs in it, one is the cruise switch backlight bulb and the other is the cruise control function bulb.

How do you change a light bulb on the passenger side mirror of a 2006 ford expedition?

There's three nuts on the inside of the door near he top (backside of the mirror). You may have to pull the door panel to access the nuts and wiring connector.

how do i replace the side mirror on 94 acura integra

Pull off the triangular trim panel that is right behind the mirror. It is held on by 2 clips. This will allow you to see all three 10 mm bolts to remove the mirror.

Inside fuse box is under the drivers side dash panel, where your left knee would be sitting in the seat.

As far as the mirror, the access to the bolts are behind where your tweeter is on the inside of the car where the mirror meets.

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

There is a panel on the inside of the door where the mirror is.
That has to come off.
In some cases the door panel has to come off also.
Under the mirror panel there are nuts that hold the mirror on. Remove the nuts unplug the harness and install the new one.

If you remove the door panel, you'll see the screws that hold the mirror on. Remove them and the mirror will come right off.