Climate Control Unit
WARNING: This page does not describe the selected car, but rather 7 other vehicles, including the 2017 Honda Odyssey, 2016 Honda Odyssey, 2015 Honda Odyssey, 2014 Honda Odyssey, and 2013 Honda Odyssey. However, it is still accessible from the selected car via links, so may be relevant.
The climate control unit is located on the center of dash, and sends a seat heater switch signal to the seat heater control unit using the B-CAN line.