I took my Oldsmobile Aurora to them because the lights were flashing on and off all the time. They told me that the multifunction switch needed to be replaced. When I picked up the car, the lights were behaving and I paid them the $800 plus for the new switch. Some period of time went by and it started happening again, so this time I did some research on the problem and found out that the grease inside the switch eventually flows, causing intermittent flashing of the lights and buzzing.
I also found out that it probably only need to be cleaned instead of being replaced and how to do it with contact cleaner and compressed air. So I went to do it myself and found out that that is what was done before (and I did clean it and it does work fine, now). So, instead of my switch being replaced, it was more likely just cleaned and I was charged for having the switch replaced. I have a distrust of dealerships anyway, and this didn't help.
I suggest that when you are told that such and such parts need to be replaced, you go there and physically put some kind of indelible mark on the part and then ask for the parts after they ""replace"" it/them.
Too bad you need to actually give them a rating. Even a one star is too good for them, in my opinion.