as I pointed out, what it's possible to know is in the shop manual, if you don't have one you should get one - you could check
this online 56 supplement to start .... I should add that the 58 & 9 wiper motors have an electrical switch, not the cable operated one that was on 55.2 - 57 ....
8/9 motor -
and 8/9 switch, so problems will vary
Bill