The driver's side heated seat on my 2010 MKS recently stopped working. I have heated/cooled seats. As I understand it the heating system works differently than in a seat that is only heated. The heat or cooling is delivered by a fan unit under the seat. In my troubleshooting I have seen the following behavior. If I start the car and then turn on the driver's side seat COOLING, you can hear the seat fan kick on and stay on and cold air comes through the seat. All works as expected. Adjusting the setting while in cooling (High Medium and Low) will correctly change the fan speed. If I turn the heated seat on I hear the fan start a few seconds later it stops (normal behavior). After about a minute or so the fan comes back on (also normal) for a few seconds and then stops and the light on the button goes out. Any subsequent attempt to test cooling or heating and the fan will not start even though the lights in the buttons come on and stay on. You must turn the vehicle off and restart it if you want the fan to work as described above. If I perform the same test on the passenger's side when I test the heat it acts much the same. The fan comes on for a few seconds and stops. Then about a minute later the fan comes back on and stays on and warm air starts coming through the seat. The passenger's seat works 100% as expected. Based on the test above it seems like the fan initially turns on and then turns off as part of an initialization process. The system must then wait for a minute while the heating element comes up to temp and then the fans kicks back on and delivers heat. I'm not sure what would cause the fan to start up the second time and then shut down for good (until you restart the car). Can anyone offer any guidance as to what the issue with my driver's side seat heater might be?

Cars & Trucks - Lincoln