Im not real savvy with relays and electrical terms, but I had this similar problem in my old 02 GP. I went through the trouble and money of replacing the blower motor and all that like you have. It turned out to be the actual HVAC unit/box under the radio head unit, the part with the HVAC climate control and airflow direction knobs, that failed. Replaced it with a new dual climate control unit or whatever it's called, and worked just fine after that. Hope this helps! Good luck