My car has no heated seats, I'm kind of glad it doesn't get cold enough here in los angeles to warrant needing them.
I would look at the connectors on your seats, and then look att he connectors nt he seats you plan on buying.
That should help you figure out if they will just plug right in with your existing stuff.
'92 300CE - Sold
2004 C240 - C7 Wheels
2015 ML350 - P1, Pano, Ash poplar wood, Sport Dinamica interior, Running Boards Keyless go.