Blower motor won't turn off

My blower motor in my 2000 buick century started on high and will not shut off regardless of the switch position. It even stays on when the car is off and the key is removed.
I suspect a bad relay but I don't have the electric diagram to tell me where it might be.

Any ideas?

Thanks

If you have a manual HVAC not digital climate control it sounds like you have a bad blower motor resistor assembly (BMR). The hi-speed relay is probably stuck and it is located on the BMR. One side of the hi-speed relay is hot at all times even with ignition to off. Good luck!

Thanks bnaylor reply.

The blower motor is a replacement I put in a few years ago. The pigtail coming out of it goes to a connector (along with another bigger wiring harness) that looks like it has a circuit board on it. It is right up against the firewall and difficult to see. Is that the relay circuit?

Thanks bnaylor reply.

The blower motor is a replacement I put in a few years ago. The pigtail coming out of it goes to a connector (along with another bigger wiring harness) that looks like it has a circuit board on it. It is right up against the firewall and difficult to see. Is that the relay circuit?

You're welcome and yes. It is the resistor matrix that channels voltage based on blower fan speed to the blower motor. Commonly called a blower motor resistor (BMR). Not too difficult to install. Just a lack of working room factor. The blower motor must be removed first.

Thanks Again,
I had the mortor out last night and don't ya know there is one screw in the back of the BMR that I just couldn't get to. I think a remount is in order on the new BMR.

Replaced the Blower Motor resistor and it works fine now. I relocated it away from the firewall (I just left the old one in there).

Thanks a million.

Ray