My husband has changed the wiper motor, checked.

My husband has changed the wiper motor, checked fuses, & some other mechanic told us there is a relay switch behine the air cleaner on the back wall but he just looked & could not find one. Any idea what else he can check the wipers still wont work and he tested the voltage coming out of the pig tail to motor & is getting 12 volts, but noticed wiper motor when pluged in sparked occured off wiper motor when contacted metal on engine. Do you think he needs to buy a brand new motor the two he tried one was rebuilt from a junk yard, both were from a junk yard. Thank you for any help Mrs. Janice Summers