Wiper motor won’t shut off?

Ok, got the motor off and checked inside.... nothing broke or missing. But when I hook the battery up the first setting of the switch sounds like it’s on the slowest setting the second and third sound the same , like it’s on the highest speed. I changed wiper switches and it acted the same, the off position and the first setting sounded like the low setting, the 2nd and 3rd setting sounded the same[ like high speed]. I ran a ground wire from the ground strap to the battery ground and nothing changed. I Really hate to buy a new [ refurbished] motor and it does the same thing.