Bench testing a variable/3 speed wiper motor

I have a spare wiper motor for my '65 Belvedere, just want to make sure it works correctly. I downloaded the FSM, but the bench testing directions don't make sense. I think there's a typo, as it has the yellow wire being jumpered to both positive and negative. Supposedly the 1965 Dodge manual describes the correct procedure, but I haven't been able to find one of those. Also, I kinda thought the black wire would be the "ground strap", but there's 810 ohms resistance between the wire and the case. Yeah, motors aren't my strong suit.
Edit- just to make this a little longer...
Red, field 1
Yellow, field 2
Black, armature
Blue, park
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