ok so my 1989 k5 blazer window motor when you hit the button it will go down but when you hit the button up the motor does nothing. I bought a new motor and the same problem exist the motor works great when you hit down but not up so what could it be?

 

faulty switch? do you have power to the up function on the switch ?

 

i have a identical k5 as parts car i took switch out of there and tired and it does same thing
i havent tried i was just thinking i could hook a drill up to it for the up function until i figured it out.. seeing as i live in st.louis and its 115 driving with back window down well if you have a k5 you kno pulls the exhaust in lol

 

Are you getting power on the up circuit in the tailgate at the motor? It is very possible that the lockout switch has failed. The lockout switch is not in the down circuit.

 

is that the switch in the door on the driver side of the tailgate its hidden 2 prong?

 

the motor is grounded to tailgate, the two wires going to it are positive, one for up and one for down. if its not that safety switch it could be that wire is cut somewhere

 

Pull the connector out of the safety switch and jump it. Then see if the window goes up.