Wiper problems Arrrgh

[Chevyguy]

It took me a while to notice this problem since it did not rain for a while after getting my Notchback running. My wipers only function in the high position, the washer works but I have to turn on the wipers manually, when I switch to low, they stop dead. My 89 - 93 Chiltons manual has no wiring diagrams of the wiper system, I have the 79-88 version too, and there is partial info on a 87 system listing a module between the switch and motor. My motor has more wires than that setup. I would prefer to meter the wires first before yanking out the switch or motor, but I dont know what wires are supposed to do what??
Does the Factory service manual cover this???
I was hoping to fix this this weekend.

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Frank W
90 5.0 LX coupe Daily driver. Silencer removed, K&N filter. Flexalite fan, 3 core radiator. FMS flywheel and Clutch Finally rebuilt T-5.

74 Chevy Laguna Type S-3 305 apart in garage, getting a 454 to put next to it
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