I have just purchased a 1988 cherokee chief , the wiper on move very slow, doesn't matter what position you have them on low or high. I'm thinking wiper motor. Any other ideas? Is there a module that could cause this.

If you grab the wiper arms from outside the vehicle, do they have some play in them?

Another thing could be the poor grounding system on your 88.

Click on the link in my signature and read posts 1 through 5 to address known issues.

Any questions, post them up.