92 Bower motor problem

I have a 92 Bonneville SSE. Recently the blower motor started acting up. It would stay on full speed whether the car was on or not. Which would drain the battery in minutes. I replaced the blower motor and now it doesn't come on at all. I've tested all fuses and relays. All of them work. If I connect 12v directly to the motor, it works. I hooked up a multimeter to the connector that goes to the blower motor and when the car is turned off, it has 12v on it. As soon as I turn on the a/c in the car, it goes to 1.4v. Does anyone have any idea as to what it could be? Thanks for any help.