Heater/ A/C blower won't shut off

2007 GM, 42,000 miles

The blower for the heater/ A/C runs at high speed all the time. Even after turning every thing off it still runs. No matter what I do it refuses to stop running. The noise is ,well annoying. It does have the digital controls. The only time the blower stops is when the ignition is off.

Any suggestions as to what to do to fix it?

Thanks.

see if it is the switch? pop the dash cover off and unplug the switch see if it shuts off.

Possibly the blower motor resistor. If it is shorted across the resistors it could cause the problem. Also there is a module that controls the fan. A high end scan tool can read all the modules for trouble codes.

Can anyone tell me where the resistor is located? I have looked under the hood on the firewall around the blower housing. Nothing. Also took off a plastic panel below the glove box and again found nothing that looked like a resistor.

Thanks

Is this a manual system or the Electronic controls?

Electronic controls.