Service light came on and it felt like the heat was on also

No. I had been driving a bit, making stops here and there (shopping). I had stopped for lunch, and when I came back out and started the car and began to drive, I noticed the heat right away. I think that I may have found my answer on YouTube. I will check tomorrow to see if the temp. gauge is in the middle as normal. If not, I will know that it is that the thermostat needs to be replaced. FYI, this guy's videos show exactly how to do it. Super easy as long as you have socket wrenches and regular wrenches. https://www.youtube.com/watch?v=e3bASQM4EYs

good luck and have fun!