Do you have a DTC U0209 showing?
If So, there is PIC5954
Effectivity: 2011-2014 chevy volt and others.
A customer may comment that both heated seats are inoperative.
This condition may be due to an intermittent software issue within the heated seat module that results in the loss of communication from the HVAC controller.
instructions:
Do NOT replace the heated seat module for this condition.
If the technician finds the heated seats inoperable and the DTC U0209 is present in the HVAC module, reset the Seat Module by removing the heated seat module fuse for 5 minutes then reinstall it.
I DTC code is not present, perform normal heated seat inoperative diagnostics per the service manual.
Btw: the Heated seat module is located under the front edge of the drivers seat bottom.