When I turn the car off and remove the key the heater/ac stays on. I turn the blower off and it shuts off but the temp display stays on. It is a 1997 Bonniville SSE.

Sounds like the controller is out. The controller is the actual panel with the buttons you push to make the air come on. Remove the trim from around it...if you dont see screws...they probably snap out. remove 4 screws that hold controller in place. carefully pull controller out enough to get to electrical and vacuum hose connections. Go to wrecking yard or E-Bay Motors...online for replacement. Installation is in reverse of removal.

Theroadisalover

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