A Mercury Milan in my bay for prep, and on my list... heated seats that don't.
A quick check of the database, no hits. Rats... going to have to do this the old fashioned way.
Wiring diagram to get a map in my head, and begin breaking down the system. First to the various fuses just for luck, and no joy. Next to pry the switches from the dash, to find the 'switches' are part of the HVAC module. Buggers.
Thats two major components left to check, the HVAC module and the heated seat module, and the wiring twixt and tween. Oh.... and the heated seat elements themselves of course, but small likelihood all of them would die at once.
Begin with a visual... monkey mechanics.... OOk Ook and poking fingers at the thingies. The heated seat module is buried under a plate, under the passenger seat, so out with the seat. Unplug the module to visual the connection.....
And just a wisp of green on a couple terminals.
Ho HO my jolly little fellow! What are you hiding in your black plastic casies I wonders to meself. Off with the snappies, pull the board..... and........ EWWWwww. THAT does not look healthy. Self, I say.... we thinks this might be needful of a new one.
Lesson reinforced: Most diagnostics on vehicles are not difficult. The majority are found out in the initial thinking, the understanding of how the system works, and some attention to details.