where is the heater core located?

Usually buried deep behind the dash. And it's a major pain to replace. http://www.justanswer.com/dodge/0yjxx-replace-heater-core-1996-isuzu-trooper.html

I hope you love your car....if it's between the dash and the firewall it's going to be very a very expensive labor charge to do this repair.

Before you go sinking a ton of money into it for nothing, what exactly is wrong with it? Unless it's dumping anti-freeze all over the floor, it probably isn't the heater core.

Good advice. I imagine that the reason you're asking about the heater core is because its not working and this forum is "maintenance and repair". I had an old T-Bird and the heater core died and fluid was leaking in the car aside from not working. I was lucky to find someone to do this for a great price, however, it's a matter of luck or do it yourself. So, you're budget and how much you can tolerate. If you live in a cold climate, you'll be highly motivated to either fix it or decide to get rid of the car. I hope you have low mileage and that your car is in remarkable condition. If you're close to 200 k, I would probably dump the car.