HOW DO I GET THE KEY CODE TO A 2008 MERCURY MOUNTAINEER

I had to deal with this. The alarm module is located in the left quarter panel area, and the door code is written on the side of that unit. You have to reach up and in to find the module and it is a bit of a pain to remove (either bolts or screws...can't recall), but that was the solution for me at a cost of some time and $0.00. If you look up a video on removing/replacing the alarm module, then it will get you to your solution. I think the battery needs to be disconnected, or would be a good idea even if not required.