On my 79 coupe the blower stopped working, so I replaced the blower motor relay and the speed control switch and now the blower blows all the time at one speed and will not shut off, even with the ignition off. Any ideas ?

 

Welcome to the forum.

Is the one speed High? Check the blower resistors and all connections.

Also check the relay to ensure that it is not stuck closed. The purpose of the relay is to bypass the blower motor resistors when you want to go to the High speed. It applies 12 volts directly to the blower motor. If it's stuck closed, then the motor will probably run all of the time.

 

Yes the speed is high, the relay is new, how do I check it?

 

You'll need an ohmmeter. If you don't have a schematic of the circuit, you'll need to take the relay apart to see if the contacts are stuck closed.

But I doubt it's the relay. You might put the old relay back in and see if it still does it. I'd lean towards a wiring problem or connector problem since there shouldn't be 12V w/ the ignition off.