Went to Radioworld to get a new cord.
The great guys there tested the old cord and cradle and it worked fine.
One even tried it in the van and this time it worked! I had tried it yesterday with no success.
Not in rental car, nor a pickup in Gilroy, nor my Caravan on return, but now it's fine.
I have no idea why. It may be an intermittent problem in the cord or cable, or a software issue in the unit that does not allow it to turn on.
If the latter, what caused the fix?