<VV> WIPER PROBLEM

[Michael Kovacs]

Today my wiper stopped at mid stroke. 
Was about 10 outside. I wanted to wash the window. The wiper only got 1/2 way thought the first stroke and stopped. The fuse is OK. By gently pushing the blade back down a few inches (taking the slack out of the mechanical linkage) it will move back by the motor and stop at exactly the same place. 
 I have spare '69 motors but what else could it be? I can't get it into my work garage due to the drifted snow and would not like to work outside today. Any suggestions?.