Hi DrRadar and all,
DrRadar reminds me one very important thing and hits the bull-eye, I think.
Underneath the car there is a hose to drain the condensation water from the AC out to the ground. A week ago, the hose got clogged (happened to my former Buick years ago too). The condensation water got back inside the car, on the passenger side. I lifted the car up, clear the clog, and solved the problem.
The blower motor is very likely damaged by the condensation water. I will try to take it out and check.
Thank you very much!
H.