My heater in my 07 Chevy equinox quit on me today. I’m not sure where to start first in replacing or looking for where it quit.. any advice would be appreciated.

 

Well, does the fan blow, what's the temperature of the engine, do you have it selected to heat, is the radiator full, just asking. You really need to post more information.

 

Is the cabin fan working?
Check the coolant level. Low coolant can result in little or no heat or sporadic heat.
Possible stuck thermostat.
Clogged heater core (not likely, but with the age of the vehicle it may have built up deposits over time). This would be the last thing I would suspect. If it is clogged you may be able to unclog it by reversing the heater lines and using a product such as Prestone SuperFlush. If it's really bad and cannot be unclogged replacing the core is the last option. This can be expensive (usually requires removing the dash to access) or if you're willing to do it yourself, it can be time consuming.

One last thing - if you are getting air flow is it coming out the floor vents when the floor vents are selected? If not, it may also be a stuck or broken blend door.

 

As previously suggested, be more specific and provide as much information as possible.

Is the blower motor not working or is it still working but doesn't blow any hot air?
Does A/C still work?
Are you still able to change modes (i.e. vent, floor, defrost)?
Does engine still warm up to normal operating temp?
Have you checked the coolant level?
Have you had any recent service/repairs performed on the vehicle?