[old gto]

When I shut the wipers off, the go down, but won`t park. Instead they jump up & down a couple inches until the fuse is pulled.
It was decided in the electrical forum that the wiper arm adjustment may be the cause, not allowing the motor to come to "park". Some members loosened theirs and say this worked.
My question is, on the 69 GP, does anybody know how, or where, to adjust these?
Thanks!