Hot news flash (no pun intended). My mechanical friction hypothesis may be wrong. I reconnected the battery (and the small wire to the motor). Without turning on the ignition or the headlight switch the motor began to heat up. So power is being applied to it. It doesn't make any noises, just gets hot .. I didn't leave it connected long enough to get really hot like yesterday when I operated the lights.
Time to look at that circuit diagram. Where is the headlight relay located? I'll confess to not being a good (or even half-assed) automotive electrician. All help welcome.