I’ve had an issue with my Toronado, my heater/ac work fine, but on the climate control I can’t change which fans blow air, or the temperature. There’s a hot/cold lever below the passenger side dash which I jammed a piece of wood into so it stays on the hot side while it’s cold out. Otherwise it’s stuck on the coldest setting. What part do I need to replace?

 

Verify the linkage between your AC control head and air plenum isn't binding. If you have to use a wooden stake to keep the temperature control in the right position I'd say something isn't connected correctly.

Also check all the vacuum lines under the dash and on the firewall. The GM AC controls often used small vacuum lines with colored stripes that controlled the air doors.

 

Did you ever get a 1978 factory Oldsmobile Chassis Service Manual? Like this?


It will tell you how to troubleshoot your HVAC system. Original print copy from 1978 only. Reprints and any digital copy are almost always inferior.

Next determine which system you have. It could have had heater/defroster only, manual control Custom Air Conditioning, or Tempmatic. Control and service procedures are different between all of them.

If it's either airconditioning system and the airflow switches between outlets that says your vacuum source is ok. If it's a Tempmatic that sticks in either full cold or full hot the problem is in the programmer, usually the vacuum checking relay on it.

Those things were a common enough failure item that most GM dealers kept them on the shelf.

I don't have a parts book covering those years. Sorry.