overheating, only when it not running, when speeding it goes back to normal

 

You're not making any sense. Engines don't overheat when they're not running. What year is your Equinox and which engine does it have?

I think what you meant to say was that the engine overheats when idling at a stop, but runs fine driving down the highway. If this is the case, your cooling fan is probably not running.

If you have a 2005-2009 model, try unplugging the harnesses going to the cooling fans and reconnecting them. Those years have a tendancy to develop a weak connection there. In some cases, enough heat is generated to melt the plug.