Hello all, I am thinking about purchasing my future mother in laws 06 s80, it has around 100k miles and in good shape. It has a strange issue when you turn the heat or ac on it keeps switching back and forth every 3-5 seconds. Hot then cold, I am assuming it could be a control module issue or interior temp sensor issue? But wanted to get some advice before hand. Thoughts ? Suggestions? Thank you !

 

A good first step would be a scan of all the control units with a compatible scanner. With a good scanner you can activate components and view live data. Could be as simple as a bad evap temp sensor - but you won't know without a good scan tool and the knowledge to interpret it.

 

hmmm didn’t consider that. I’ll have to see if I can find someone around me to scan it.