Engine revs and the heater is not working

Hello,

This high RPM issue could be triggered by a faulty idle air control valve. On this vehicle the idle speed control is part of the throttle actuator.

https://www.2carpros.com/articles/engine-idles-too-high

It is a possibility that this is triggered due to having a dirty throttle actuator. When the component of the actuator gets dirty it is unable to send correct data to the ECM and that can lead to erratic idle.
Try servicing the throttle actuator by cleaning it out.

Here are couple of helpful articles:

https://www.2carpros.com/articles/how-a-throttle-body-works
https://www.2carpros.com/articles/throttle-actuator-service

I have attached diagrams for your reference.

Please let me know if you have any questions.
Thank you.