My wife and I went out for a long drive last Saturday. It was a little cool, so the wife and I both turned on our heated seats. I was driving, she was in the front passenger seat. After "awhile" (at least 30 minutes), her seat heating cut off, but mine did not. She could not turn it back on, and have it stay on. As soon as she would hit the button, the three lights would lite up, then immediately cut off. During this time, mine remained on. We also tried voice command - same behavior.

Is this normal behavior? I know my wife is hot, but this seems odd that mine would keep working and hers would not,

What I found in the owner's manual is not the behavior that we experienced, but I reserve the right to be wrong.

 

While I do not have this model, this would be abnormal imo. Your driver seat is acting correctly. Thats how all of my Mercedes have acted. The with is regulated by a timer and not temperature.

 

Evidently, the new ones can overheat and will shut themselves off before they do. Maybe.

 

The passenger seat in my '23 EQS sedan demonstrated the same symptoms. All the indicator lights on the door would illuminate and go through their progression down to "off", except there was no heat being delivered. A service call on the issue revealed that a wire connector underneath the seat had become disconnected. The dealer plugged things back together and everything works fine again. Nothing gets blindly shoved underneath that seat anymore.