PROBLEM SOLVED!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

Thanks guys. I neglected to reveal that the DW was working fine until
I removed it last month to remodel my kitchen. It sat covered with a
tarp on my outdoor patio the whole time.

I followed your advice to remove the motor & pump assy and see if the
shaft would turn freely by hand. It WOULDN'T at first, then it
suddenly broke free. Guess the cold weather and inactivity caused
something to temporarily bind. Anyway, after cleaning it and putting
everything back together, it's working normally. Good thing: the
motor alone is about 80 bucks plus tax & shipping and the motor with
pump attached goes for around $135. A complete new DW of the same
make-model is $549 at Lowes; that would have probably been the way I'd
have gone, considering the machine is 4 or 5 years old already.