I AM a manager at a car dealership, so I have seen both sides of the "Sales Practice."
The first question I have for the OP is this: I assume you purchased a new vehicle.
If you did was heated mirrors listed on the Manufacturers window sticker also known as the Federal Maroney Label or was it on a seperate dealership stick on sighn or addendum label?
If it was placed on a dealer label or addendum sticker your compliant needs to be addressed to the manufacturer, but demanded to the dealership as they are liable for improper markings. (the same senario if the car is used, then the manufacturer is really out of the equasion)
If it was printed on the Federal Maroney Label you should use your dealer as a gatway for the manufactuer to fix the issue, as they are the ones that made the mistake, not the dealer. The dealer sells the cars and sell what is placed on the cars via the manufacturer. If the sales person saw heated mirrors as part of the Maroney he was simply selling what was on there.
Now for sake of good customer service I, as the dealer, would be speaking to the manutfacturer regarding this issue to try and get it resolved. However understand that due to same practice laws, at least in Illinois, if I as the dealer fix your car and pay for it, I am legally obligated to pay for everyone else who has the same problem wich I am sure there is.
If I were you I would try to get the name of the Manufacturers dealer relationship manager. That might give you a good start in finding out what they will do for you. Obviously they know the problem or they would not have changed the Maroney lables. I would bet they have some compensation plan in place. It happend to one of my cars once with heated seats. I was told by the manufacturer to put them in and I was reimbursed for the cost.
let me know if I can halp you.