I'm not sure whether GM is at total fault here, who is their supplier for those switches mentioned? Company name? Has GM changed from buying from that company since the end of production? Our cars were parts bin specials, whatever fit, and was within budget for the platform, well there you go.
Each owner has their own unique experiences with certain switches that don't function properly.
New car right from the factory, I am sure that any car might have a problem with a switch, if found by the dealership, replaced under warranty.
Used car with maybe an unknown history from the previous owners as to what worked, or has been repaired or replaced by that owner?
TS is right here, in that they are plastic in nature, and maybe from over use from the previous owner, or lack of use by that owner they do break, and can be taken apart, and repaired or replaced by you. You know the dealership will replace them in a heart beat, and put a dent to your c/c $$$.
Check your switches, lights, functions of such, weekly or monthly is in my mind, owner related before you drive and smile. How do you know, IF they work, IF you don't test them on a regular basis? Then you know, this switch won't work right, or that left turn signal bulb is out. " The reason why I pulled you over today sir, was your left brake light is out. Here is your ticket/inspection notice to get that fixed right away... $$$ You have a nice day sir!" "Why yes officer I will", while you truck down to Advance Auto or the like to find the replacement bulb in question. Know what I mean?
Mirror/door lock/fog light switch, all open to the elements when that side of your car door is open. A heavy moisture build up, high humidity or rain every other day, salt sea environment could have caused corrosion build up on those switches and maybe others too? A leak maybe have developed on that side of the car/window seal letting water/moisture seep in to the door/interior maybe? Any signs of water damage or... flooding might have gotten to that side of your car?
We know that certain things on our car do and can go wrong from time to time,..." You don't say LAC?" Imagine that! Every car or manufacturer has some issue at one point in time, MB or Ferrari, Audi, Ford, Chevy.... water pump here, cracked fender there, PPS seat mat sensor, fog light switch to the left of me, ignition switch to the right of me. I for one have not had any problems with switches on my car so far, that's just me, lucky I guess. Now as far as the air bag/pass. seat sensor mat ( thanks to our man Robo ) that has yet to be determined on yes it does work, or nope it's gone like the wind. Fix it at N/C !
From your description it sounds like corrosion build up, or a broken contact could be the problem? Source the replacement part # and price, for now just in case? If possible remove and inspect the switch, open it up check what you can see inside, if a "plastic " piece is broken( TS ), or if there is a heavy corrosive build up of some kind? Check the fog light bulb/socket/wire connections for anything that looks suspect to you.
Being that this IS the fog light switch, it does not interfere with the most important function switch on our car. The ignition switch works just fine
Hope you find your answers to this problem(s), driver's door window/lock switch, driver side mirror switch, driver side fog light switch is there a pattern developing here?
Fixed or replaced by you at cost/time plus or minus a few beers
along the way, " Damn... it's always something I gotta fix before or after I drive this thing." Yup I've been there before, think we all have at one point in time, or with that "special pos " we all have had, that no matter what you did, or how often to you tired to fix it, it never ended good for us, thank god that car was finally put down, for my sake, my bank account sake, for my sanity...
not that I would like... put a .357 hole straight through the engine block Oh No... not me!
Many cars, many problems some good, some not so good. It comes with ownership.