Well, my fiero has been sitting for a very long time and was dirty and had a few leaves and other junk on it. It has been cleaned up and one problem was noticed when I attempted to turn on the heat. I first heard a noise like there was garbage in the fan (leaves or something) and then shortly after some light smoke started coming from the middle vents. From under the front hood I could also see a little smoke coming from the 2 tubes that run to the heater core....almost like a smoldering of something.

I remember a long time ago reading about debris sitting somewhere and causing a similar problem but I wasn't sure what I should tear off and remove to clean out. I don't believe it is a bad heater core but I guess I can't yet rule that out either.

Any ideas?

Probably debris around the resistors in front, they get hot enough to start a fire. I would pull the blower motor out the front, as well as the resistors. The resistors are just a flat diamond shape plate visible in the spare tire area held in by I believe one screw.

With the plate and blower motor out you should be able to pull any debris out of there.

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Looks like you need to clean out the ductwork. The job goes a lot easier if you use a vacuum cleaner with a long hose.

Sounds like a mouse has made a nest in heater duct and or heater motor .Take heater motor out and clean duct work and heater motor.