Wiper Issue on 1990 Volvo 760

I have one wiper that works, one that does not...what do I need to look at?

Asked by for the 1990 Volvo 760
check the wiper linkage make sure it is correctly hooked up and none of the bushings are bad in the pivots
1 more answer
Sometimes it is simply the retaining nut working itself loose. Check and tighten if the case.