I found a lot of good information doing a search, but unfortunately as a new owner this wasn't something I knew would be a problem so I didn't search until after a bit of a scare today. Maybe some other recent new owners will see this and avoid the experience I had.

I bought my car from a guy in Minneapolis who stored it winters. He told me when I spoke to him that he'd had mice take up residence in it but had the nest cleaned out. Rob (MinnGreenGT) checked the car out for me and noted a bit of "mousiness" in the vent air, as did I when I got the car. Unfortunately, I just assumed it was residual smell and have been happily playing with the car (and some fabreeze masked the smell pretty well). I even recharged the AC (original R12) and didn't notice anything out of the ordinary.

This morning I pulled out of the garage and turned around to go to work and smoke started coming out of the vents (was a bit cold so I'd turned the heater on). I quickly turned off the heater, shut off the car, and opened the front compartment. Luckily, the smoke quickly stopped. After getting my heart regulated again, I pulled it back into the garage and took another vehicle to work.

At work, I started searching PFF a bit (slow day) and found lots of info about heater boxes, resistors, and fires. I even called my wife once to make sure the garage wasn't burned down. When I got home and investigated, this is what I found:





I don't know why the fire stopped, there was a lot of fuel in there and you can see some of the burnt stuff. Luckily it appears there wasn't any damage (although the mouse smell has been replaced by a faint burnt smell). I removed the blower as well (date code indicates it was replaced 2016 or later) and there was a bit of stuff in there as well, although not what I would consider packed.

So, I've vacuumed out what I can see, although I haven't taken the step of running a coat hanger around the heater box as some suggest. My main question is can I get it clean enough without removing the front heater box cover? That seems to require removing the AC components, which as I indicated above I just recharged. Are there other trim pieces I can remove to get in there better?

This is a HUGE issue and has cost many people their cars. That is the most common place for mice/rats to set up a nest and that resistor gets red hot.

See this thread
https://www.fiero.nl/forum/Forum2/HTML/130275.html

[This message has been edited by IMSA GT (edited 01-07-2020).]

quote Originally posted by Fiero Ag: I found a lot of good information doing a search, but unfortunately as a new owner this wasn't something I knew would be a problem so I didn't search until after a bit of a scare today. Maybe some other recent new owners will see this and avoid the experience I had.

Thanks for posting this. Even longer-term Fiero owners like me have forgotten to check this out ...

quote Originally posted by Fiero Ag: My main question is can I get it clean enough without removing the front heater box cover? That seems to require removing the AC components, which as I indicated above I just recharged. Are there other trim pieces I can remove to get in there better?

No and no.

My Formula (with A/C) wasn't all that bad when I took the heater box apart, but nevertheless, I'm glad I did... as linked to Above.

Okay, so you just recharged your A/C... but do you really wish to be breathing in dead mouse bits (or at the very least, mouse sh!t) every time you turn on your heater.

[This message has been edited by Patrick (edited 01-07-2020).]

Pull blower motor and resistor pack. Use camera/mirror thru blower opening to easily see affected area.
https://www.fiero.nl/forum/Forum2/HTML/141959.html

search: blower resistor fire

But...
Mice/Rats is another story... Nest can have germs etc that can kill you.
read farther down same page https://www.fiero.nl/forum/F...HTML/141959.html#p17

------------------
Dr. Ian Malcolm: Yeah, but your scientists were so preoccupied with whether or not they could, they didn't stop to think if they should.
(Jurassic Park)

The Ogre's Fiero Cave

[This message has been edited by theogre (edited 01-08-2020).]

I also discovered a mouse nest in my heater box when I bought my car last year. I got it all cleaned out. Has anyone found out what path the mice use to get in there and can it be blocked?

quote Originally posted by DukeHog: Has anyone found out what path the mice use to get in there and can it be blocked?

Mice can get through cracks the diameter of a pencil... and through rather small holes as well. Great sound effects in this video.

quote Originally posted by DukeHog: Has anyone found out what path the mice use to get in there and can it be blocked?

Path is just about any opening in front or cabin and not just heater box.

Many Heater mode doors not just Fiero are make to "leak" so even if blower is off and set to recycle you always get some fresh air from outside. Mice can likely get thru any/all doors because off this w/o chewing a bigger gap and nest in the biggest space in the box. Most times that's in the blower area of most cars but not always.

Wiring/cable/pipe pass thru seals often has small holes. Even not, they can get chewed open then look for a nest zone. Besides heater, mice/rats use space under seat(s), Under console, and more and go unnoticed for years or decades unless have to remove them to do whatever. You just don't hear them often because most aren't a fire hazard in Fiero and many other cars.

[This message has been edited by theogre (edited 01-09-2020).]

quote Originally posted by DukeHog: Has anyone found out what path the mice use to get in there and can it be blocked?

The Fiero doesn't have a cabin air filter. So it's really easy for critters to get into the ductwork. The HVAC system draws air from the "gutter" at the base of the windshield. And that "gutter" has 2 drain hoses (one on either side) that are big enough for a mouse to easily fit through.

Fiero AG, instead of probing around with a coat hanger, pick up a bottle brush and use that. The end is blunt so it's less likely to damage the heater or AC core and the bristles will capture a lot of small stuff that the coat hanger won't pull out. You may even want to remove the heater box cover underneath the dash to see if anything is in there and if you're getting debris in or coming from the vents.