wiper motor do not come on put one in from junk yard worked great for 1 month than just stop .1993 jeep cherokee and howcan i test wiper motor?

 

Why not just buy a new motor from Rockauto and then you know it's good. They're not that expensive. You can always buy one from a parts retailer (Autozone, Advance, Napa) and probably get a lifetime warranty.

You can test it by jumping it to a battery or plugging one into your harness.

 

Picking electrical items from a yard is always a gamble if you dont test them, or cant test them for whatever reason. I dont know about the wiper motor, but you can test window motors using the battery out of a cordless drill. Buying from a parts store is always best for the larger stuff. If theres a problem, you can return it and/or get a replacement. Last time i checked, a couple months ago atleast, Rockauto doesnt pay return shipping, and they dont reimburse you, so thats something else to think about.