I sampled the voltage at each headlight motor and they were identical (though trying to see it with a digital meter is tough...analog would have been easier, I think). So, since the voltage to each motor was the same, I began to wonder how one motor would respond differently to the same voltage. Upon further examination, I found that the fiberglass panel beside the motor has a small extrusion (about 5/8" in diameter, approx 1" in length) that acts as a "stop" for the elevator linkage. On my problem light it had broken off and was lying in the bottom of the headlight enclosure. Fortunately, this stop is molded with a 1/4" hole through the center, so I ran a screw through it and fastened it back to the fiberglass panel it fell off of. Works great now.
Apparently, if the motor linkage doesn't hit this stop, the headlight control logic leaves the light to a "safe" position (up) when its turned off.
Your idea about comparing the motor voltages got me heading in the right direction. Thanks!
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