The seats have filters for the temp control. Located under the seat, adjust seat to it's highest position you should see a round filter thing. I would check it first and see if its dirty before replacing. Also, if you unzip the seat back covers you will see the duct work, there is a filter on those also but I dont have any info for a part number.
The under seat filter part # 7L1Z-19E880-A ( same # for both seats). About $20 each from online dealers.