1990 Holden Commodore Heating problems

Hello, I have just bought a vn commodore second hand and while I was out picking up some things I left it running. The temperature guage always sits just above cold (which in not sure if its working). While it was left running the temp guage rose a little bit to a quater of the way up but the car smelt very hot and then the engine light came on for a few seconds then went off then came back on. As soon as I got driving again it cooled back down and the engine light didnt come back on again. The thermo fan didn't kick in but could that be because the temp guage didn't read that it was hot? Also why would the engine light have come on. Thank you for your help!