The dealer replace the blower motors on both seats and it still doesn't work? I hope you didn't pay for that.
My guess is the control module under the seat or the HVAC in the dash that sends the signal to the seats. Sometimes the wiring for the seats gets messed up and shorts something out so I would have that checked too. I'm pretty sure the technician can run a self diagnostic on the HVAC unit to see if its still in communication with the module under the seat.
Also I don't believe the Expys have the traditional seat heating element. Per the service manual description - The climate control seat system is able to heat and cool the front seats. Each climate controlled seat is operated by push-buttons on the HVAC module located on the instrument panel. Each front seat temperature is then monitored and controlled by the dual climate controlled seat module (DCSM) located on the passenger front seat track.
The front seat cushions are equipped with a plenum (duct) attached to the cushion frame suspension wires (serviced with the cushion frame). Air from the cushion thermo-electric device (TED) and blower assembly is routed through a plenum and into the manifold fitted within the cushion foam pad (serviced with the cushion foam pad). The front seat backrest TED and blower assembly operate similarly by routing air directly through the backrest manifold (serviced with the backrest foam pad).
The climate controlled seat system contains the following components:
HVAC module
DCSM
TED and blower assembly within each front seat cushion and backrest
Air filter (attached to each TED and blower assembly)
Cushion and backrest foam pads (includes manifolds)
Cushion and backrest trim covers



Matt