I want to say it was a factory option on the Escalades and Denalis but don't quote me on that...
I think I've been told that before.... I did look up the Tahoe on Rockauto, but I didn't see anything specific mirror-wise for the Denali. (I only now recall that it's a GMC Yukon, not a Chevy Tahoe) I didn't think about the Escalade. I'm guessing I'd have to go OEM to get that. The wiring wouldn't be there in my truck, so I'd have to figure that out.... even with these aftermarket grids. It's cold out, and I'm working 6 days a week out of town, so I don't have the time for it, now. I've got parts and pieces sitting here next to me that I need to install on my two vehicles as it is.
I've had heated mirrors in one vehicle before... my 86.5 Toyota Supra. They never fogged up or stayed iced over. I didn't know why for the longest time