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Thermador Oven SMW272 Won't Heat, Stuck on Preheat 100


Premium Member
May 24, 2021
Model Number
More than 10 years
Hello, I have a Thermador wall oven, I've followed a previous post on what appeared to be the same condition. The post is from a few years ago and is closed now. I've tried to follow the same steps to fix but no luck. Here is the condition and what I've tried.
I can turn on bake, the cooling fan comes on, preheat 100 comes on, I hear relays clicking, no heat. I turn on broil with the same results. I try convection bake, the cooling fan turns on and the convection fan turns on, the convection fan will turn off when the door is opened, but no heat. I turned on the self clean, the door latch locks, but no heat. The warming drawer works fine.
Here is what I've tested and tried: I replaced the SFR from one that rickgburton suggested from Amazon but it didn't fix it. I've tested the L1 to Relay Board in bake mode and out to elements @ 120v, I've tested the L1 to L2 @ 240v, tested the cooling fan @ 120v, the SFR NO to ground @ 120v, SFR COM to ground @ 120v, SFR yellow to white wires @ 120v (previous thread said this should test @ 220/240v but I can't see how that should be 220/240v from the drawing, it looks like it should be 120v but maybe I'm missing something). I pulled the oven out and checked the sail fan, it was a little gummed up but I cleaned those areas and it seems to work, I can hear the relay on the board when I activate the sail switch.
Is there anything else I can test or does it sound like I need to send the relay board in for repair? My wife really doesn't want to spend 4k to replace it but she's losing her patients with trying to repair this one. Please HELP!