Ive got a 2017 Screw with the electronic manual heat. I noticed one morning the heat didnt seem warm, but it came back. Over the course of the next few days, it happened more frequently, and ended up being pretty consistent. It got to the point where it blows cold on the drivers side, through any vent (floor, dash, defrost) but it blows hot as hell on the passenger side the same time its cold on my side. Wondering if anyone has experienced this. If I had dual zone climate, I would think maybe one of the blend doors is shot, but I have single zone climate. Its at the dealer now and they verified it, but they are waiting on an answer from ford. I found tsb 17-2133, but that seems rather specific to when its very cold out, and the heater core is the problem. Id think my hc is working fine if its hot on the passenger side.

 

Well, despite no responses, I thought I'd update. They emailed ford, who advised them to follow the tsb, even though the symptoms aren't exact. I'm told the truck has two heater cores, even though I don't have dual zone climate. Maybe because the cubic feet of the cab is so large.