Over time there has been lots said about keeping the climate control system clean of debris. Pennocks is full of information but very little has been posted on this forum. I just want to open the eyes of some who may not be aware of the fire hazard that can be lurking in your heater box, especially newer Fiero owners.
The problem might be more common in a car that's seldom driven. Mice or Chipmunks will frequent the car more often, even making living and birthing quarters in it. If you are seeing debris in your dash vents, it's time to take action without delay, but don't wait until you do see debris.
There is a ballast resistor accessible in the front compartment. On AC equipped vehicles, it's just to the passenger side and toward the bottom of the silver canister or accumulator. It will have a harness with several wires going to it and 2 screws that hold it in place. This is the true danger area. There are 3 coils on the back of the plate. These 3 coils are resistors for the 3 lower speeds of your heater and AC blower motor. When either of the 3 lower speeds are activated, the corresponding coil glows red hot, just like a coil on a hot plate.
Little critters can climb up through the larger rubber cowl drain tubes that are visible on either side of the front firewall. Once up inside the cowl, they can gain access to the inside of the heater box. Leaves and other debris can work its way into the cowl area around the opening between the bottom of the windshield and cowl cover, around the front decklid latch, and several areas along the lower edge of the cowl cover. If you succeed in keeping it out of these areas, critters will bring their own. They will steal insulation from inside the vehicle. Climbing through the footwell vents and getting padding from behind the carpet, seats, or anywhere in the interior.
The best way to clean out the system is to remove the heater box cover underneath the passenger side dash, remove the ballast resistor and remove the heater motor and its attached fan. For some reason, the critters love to build their nests around the resistors. Debris pulled in through the upper cowl has to pass by these resistors and it often doesn't get by and lodges in or against the resistors. Should any of this debris catch fire, it's near impossible to extinguish because it's in an enclosed area.
During the RFTH 23 Rerun, being a cold day and a rainy day, both the heater and defroster were in regular use on my 86SE. It worked well with no indications of any problems or any burning smells coming through the vents. I can say that I got a warning on my 87 when I smelled leaves burning. When I removed the ballast, I found leaves caught in it and they had already shown signs that they had smoldered. Back to the 86, though.
At some point late in the rerun, my blower motor started to make some horrible screeching noises. I didn't take long for me to realize that the motor bearings had failed, so today after Church, I pulled out my spare and set about to replace the old one. Now, I've been driving this car on a fairly regular basis, but in the early years, it sat for a couple of years until I got a motor for it, and prior to that, it sat in the previous owner's garage for an unknown lenfth of time.
It didn't really surprise me to find debris when I removed the motor and blower, but when I felt over toward the resistor, I was horrified. I could feel nothing but debris. I have no idea how my climate control system worked at all. When I removed the resistor, debris was all around it. Some of it had actually melted to the coils, making a bridge between coils.
Below is what I got out of the area. My 10 1/2 foot is there to give you some perspective of the size. The horizontal view is about 5 inches high. Lots of hair, some automotive insulation, leaves, bits and pieces of seeds and acorns and pine needles. I have no idea where the hair came from unless it came from the previous owner's period of ownership.
A thread from Pennocks.
http://www.fiero.nl/forum/Forum2/HTML/141959.html
