<s>[INST] I'm having a bit of a issue with my car's temperature control system. The heater doesn't work, and the air conditioning blows hot air. I'd like to know the common causes and how to troubleshoot this issue. 

Here is some information about my vehicle:
- 2011 Toyota Corolla
- Automatic transmission
- It has a cabin air filter
- No unusual noises, smells, or leaks

With this information, I could you walk me through some troubleshooting steps and potential causes?[/INST]