This happens when the seat heater control module goes out located in the drivers seat or in the drivers door. Here is its location (below). Once you replace it you may need to have it reprogrammed.
Here is the seat heater wiring diagrams so you can see how the system works.
Check out the diagrams (Below)
Please let us know if you need anything else to get the problem fixed.
Images (Click to enlarge)
Monday, February 19th, 2018 AT 3:26 PM