Since I wrote the above, the heating and cooling failed just on the driver's seat. I knew it wasn't the DSCM because I already went through that and knew that would affect both seats. The heat lights would stay on for 10-15 seconds and go out. Cooling would stay on longer, but eventually it would stop as well. I could hear the fan motor surging when I turned the cooling on. I decided to swap the "Cooling module" (the fan module, 9L1Z-14C724-C) between the passenger and driver's seats. The problem followed the driver's side "cooling module" to the passenger seat and now the driver's seat heating and cooling works. It's the same module on both sides. It's held in with just plastic hooks on my '11 EB. I unbolted the seats (takes a T55 torx plus) and tilted the seats forward to get access. Disconnect the cooling module electrical connector. Unhook the right side of the module first from the cushion spring by squeezing the cushion spring inboard, then slide the module to the left. Sliding it left will disengage the module from the seat vent and the hook that's on the left side of the module. I have the Ford shop manuals and there is nothing in there that describes this correctly. They want you to pull the seats and disassemble them to get at the cooling modules. No need. You can probably do this job in about 45 minutes, including vacuuming up all the french fries, m&ms, jolly ranchers, coins, and whatever else has landed where you couldn't get at them for the last seven years. The only tools you need are a T55 socket, a ratchet and maybe a torque wrench to put 30lb back on the seat bolts when you're done. Not only does the seat heat work, but it smells better without all that organic material under it. I will buy a new cooling module (@ $150) for the passenger seat when I get around to it.