My interior dash A/C, hi/low knob turns but no longer changes the speed of the air flow. The other two knobs (direction of flow and temperature) work just fine. any help?

Possibly, but I would check and see if there is a blower motor resistor first, they cause the same problem. I don't know Toyota well, but do know about blower motor systems.

Yes, it does have a resistor. The next window will show a link that is ridiculously long but will show one of the many places to buy one

https://www.google.com/shopping/product/3502757829934180417?q=2010+Toyota+Corolla+HVAC+blower+motor+resistor&biw=1920&bih=940&dpr=1&prds=paur:ClkAsKraX2y3oiTcpfpASOPX93pFZffEcr7sl_x4F2fPGTk8-OeZPCAgIjENsJm-Uu4neB6kBM86c8kS0rGFEKk_Ajxy9xTnRAG5XGXpGa0nsPCSjBK7Umvk0xIZAFPVH701mehtrgg023L-P425SU72zTf4Gw&ved=0CAUQpitqFQoTCLfFyreY5ccCFciYgAod2wIC1Q&ei=1abtVfeGLMixggTbhYioDQ

https://www.youtube.com/watch?v=oN00qfrYOzM

http://www.oreillyauto.com/site/c/search/Blower+Motor+Resistor/02627/C0039.oap?model=Corolla&vi=1444170&year=2010&make=Toyota

Generic information... not Corolla specific but informative http://www.samarins.com/glossary/blower-motor-resistor.html

I have been looking everywhere for Corolla specific installation instructions but no luck - This is Tacoma, should be same or very similar - https://www.tacomaworld.com/threads/replacement-of-hvac-blower-motor-resistor.8310/

Good morning Rowefast. It's really similar to most any car.

Its a new car and I do not know how to turn on the air

DId u fix it ? I have the same problem