yesterday i noticed a burning-leaf smell as i drove down the road, and soon a cloud of smoke was billowing out of the heater vents! i managed to pull over, and apparently no harm was done except to lady lurker's equanimity.

how does this happen?
ive put 2k miles on this car in the last 3 months, have run the heater many times, and i'm scrupulous about removing leaves. i assume there was leaf debris in the heater ductwork which made its way into the fan motor? how do leaves get in there?

BTW, be sure you get and carry a fire extinguisher. we didnt need it this time

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'84 2m4 se, a work in progress http://www.mtsu.edu/~mkr2c/fiero.htm

There are 2 coils in the heating ducts that create resistance so you have the different fan speeds, they can get hot and I have heard they gan glow red (they are basically the same thing as what is in your toaster). If you have leaves stuck in them, or touching them, they can smoulder, or even catch fire.

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Details on my 1984 Fiero 2M4 Sport Coupe #1192 Here
Long live the Duke!! 2.5L Upgrade coming soon I hope.
1986 Fiero 2M4 Coupe, 2.5L 5-Speed
Member of the Edmonto Fiero Club

Rate me if you want!

Lurk,

I had a similar problem on my 88. There are resistor coils that are just to the right of the blower motor. They give you your med and lower speeds and get hot when they drop the voltage. They are on a mounting board and it is held in place by two screws. Some trash had managed to get into the coils and when I put it on low or med, the heat would smoke the trash.

I don't know if an 85 (isn't your car an 85?) has this set-up or not, but if your blower motor isn't going south, I'd check it out. It's an easy pull.
Two wires and two 1/4 or 5/16 screws.

TGraves

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__________________________
88 GT V6 Crazed-Alligator white

DIY Leather Interior Available

Shipping weight..1200-1500 lbs. Freeze-dry specials!!!

I'll have to give a look to my blower motor resistors. I've owned four Fieros over the years and I've never had a fire problem...until recently. My latest fiero is an 84 and my latest home has lots of trees. The deck lid seems to funnel the leaves right down to the cataclysmic perverter! I recently had some *excitement* different than what Pontiac had imagined. No harm done though...

Yes, everybody should pull that blower motor resistor.

I never did untill I read about it here on PFF one day a few years ago.

I was surprised the amount of leaves and flammable things I found packed in there.

I have been pulling these from customers cars on a fairly regular basis, and I always find an alarming amount of stuff in there.

quote Originally posted by jelly2m8: Yes, everybody should pull that blower motor resistor.

Just to clarify: you pull it out, clean up inside and put it back right? Just wondering if there was a better way to wire up the fan control to eliminate the coils.

quote Originally posted by Stinkin_V8: Just to clarify: you pull it out, clean up inside and put it back right? Just wondering if there was a better way to wire up the fan control to eliminate the coils.

Haha ya, put it back in too. After you clean the crud out though.

I was surprised how much debris I had in my A/C/Heater
box too. I guess it gets in there from the fresh air
ducts. I am going to put some screen mesh to try and
keep it from happening. These are the rubber tubes
that go down to the bottom of the front trunk. Is
there any other way for debris to get in the box???

uh, yeah they have to be reinstalled

If somebody had the electronic knowhow, you could come up with a solid
state voltage control. I don't think it would be very practical unless the part is not available anywhere.
It's just not something that gives a lot of trouble unless something touches the coils.

Does anyone know of a good site with schematics with simple electronic controls for things like driving relays and such? Especially for autos?

Might be handy.
TG
TG

LOL.........YEP....THEM THAR FIERO'S THEY'LL CATCH FIRE ALRIGHT.......LOL.

So far I'm holding up fine, like I said and of course I give it hell......

Phil

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87 FIERO GT 2.8 5spd

If you found my advice helpful, please take the time to give me a positive rating. Thanks

quote Originally posted by TennT: They are on a mounting board and it is held in place by two screws.

it's an 84 w/ ac.

where is this marvel of engineering ingenuity located? i found the blower motor in the front compartment, even opened the cover inside the passenger footwell and saw the heater core. but either didnt see, or didnt recognise the blower resistor.

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'84 2m4 se, a work in progress http://www.mtsu.edu/~mkr2c/fiero.htm

[This message has been edited by lurker (edited 12-20-2003).]

quote Originally posted by Stinkin_V8: Just to clarify: you pull it out, clean up inside and put it back right? Just wondering if there was a better way to wire up the fan control to eliminate the coils.

If you run your fan speed on flat out, it does not go through that resistor. It is a seperate circuit. But the fan sounds like a hurricane on full speed.

I suppose you could find a place to mount the resistor block somewhere else, so it is not in the heater ducts, but I would think it would need air flow for cooling.

quote where is this marvel of engineering ingenuity located?

It is located between the A/C drier and the front compartment light. I believe it has four wires in a grey connector.

I checked mine over the weekend and found leaves around it. Other GM cars have the resistor mounted higher in the housing, but it's more fun if the location creates a fire/smoke hazard!

quote Originally posted by befarrer: I suppose you could find a place to mount the resistor block somewhere else, so it is not in the heater ducts, but I would think it would need air flow for cooling.

That's why it's there.

thanks, i found it. took out the fan and resistors, and about 1/2 cup of finely ground leaf litter, just the thing for starting fires. pix when i get in to put them on the server. whole procedure took about 10 minutes once i figured out where everything was.
i love 1-tool repairs.

couple of pictures
blower motor in located in front compartment.

resistor location. the resistor is the flat ovoid bit w/ grey plug & blue, orange and green wires immediately to left of AC cannister.

resistor out of car. interesting in a sci-fi sort of way...

small sample of flammable debris removed from ductwork

Sorry I wasn't clearer in my earlier post Lurk, but you found it.

Nice pics, btw. What camera you use? What settings (if not programmed)?

quote resistor out of car. interesting in a sci-fi sort of way...

Yeah, looks like a coil pack out of ancient Ham radio gear!

TG

[This message has been edited by TennT (edited 01-06-2004).]

quote Originally posted by TennT: Sorry I wasn't clearer in my earlier post Lurk, but you found it. Nice pics, btw. What camera you use? What settings (if not programmed)? Yeah, looks like a coil pack out of ancient Ham radio gear! TG

the descriptions were clear enough for me to find it, so i'm happy. i just figured i'd put up some pictures for the next guy.

the camera is an Argus 3550, 2.1 megapixels with 3x optical and 2x digital zoom. has USB port, uses compact flash cards. i got it at staples in tullahoma, and there's a story to go with it.

in june it was on clearance for $149, but they didnt have it in stock. they did a computer search and found one at another store about an hour away. i went to get it, and this store was out too. i settled for a similar camera by panasonic which failed during the 140th reenactment of the battle of gettysburg, so i returned it for store credit. about 2 months ago, i was back in the original staples, and they had an in-store sale on the argus, but none in stock. i persuaded the manager to track one down for me, which she did. final price? $49.95! worth every penny, AND the aggrivation. these pictures are resized to 45%.

Lurker, thanks for postin' those pics!

Good thread!! The 'new' 84 I got had leaves all over the area under the windshield & inside the storage area, so I need to do this too. Lemmee tell you from experience--don't ever pick one of those coil assembies up with the blower on. They leave nice little coil shaped burns on the ends of your fingers!!!!

Exactly where is the entry point for all that stuff to get in there?? Any possible way to put a screen on it?

[This message has been edited by maryjane (edited 04-22-2004).]

ok call me stupid I still don't know where you guys are pulling this from.. I want to check mine, now only if the weather stays nice instead of this 80 degree 1 day and 50 the next

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88 5spd Modified 3800 Series II Supercharged Formula

Front compartment. Facing the windshield--Left side, on the wall under the passenger side windshield wiper. Pull the blower motor out & reach inside the ductwork.

[This message has been edited by maryjane (edited 04-22-2004).]

ahh ok, I'll have to take a peek been driving the car for 5-6 years and never checked this, could be scary

quote Originally posted by TennT: uh, yeah they have to be reinstalled If somebody had the electronic knowhow, you could come up with a solid state voltage control. I don't think it would be very practical unless the part is not available anywhere. It's just not something that gives a lot of trouble unless something touches the coils. Does anyone know of a good site with schematics with simple electronic controls for things like driving relays and such? Especially for autos? Might be handy. TG TG

GM does make a solid state fan speed controller. It is used in any vehicle with automatic climate control, or if it has an "infinite" fan speed adjust (I have an S10 with this) instead of a lo/med/hi click switch. The solid state controller has a heat sink, and is still mounted inside the fan air box for cooling but I doubt it gets as hot as the resistive coils. The coils really get hot if the blower motor gets stalled out from lotsa debris, mice, or lack of lubrication/bad bushings.

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Tim
Red 88 Formula Auto 2.8 100K+ Miles - Hypertech - No Cat - No EGR

Logic is a systematic method of coming to the wrong conclusion with confidence!

Thanks for the post and pictures, I never heard of that before.

The vent under the hood was full of leaves when I bought BlueGT. Pine needles are the worst because they manage to make thier way through the screen. It is a really good idea to check the vents, especially if you park your car outside or near trees. Luckily I had it in the shop when I discovered the massive amount (I'm talking handfulls) of leaves in the wiper motor area. I cleaned out what I could by hand, then remved the blower motor and used air from the air compressor in the shop to clean out all that was in the system. It will make a mess everywhere when you do that (even inside the car), but it works. I'd rather spend a few hours vaccuuming the car than watching it burn to the ground. My friend Nissan truck caught fire because of that same problem... Luckily he had a bottle of water with him and he poured it into the vent system and managed to put the fire out before it had a chance to do major damage.

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BlueGT

wow pulled mine out clean as a whistle I was getting ready to pull the camera out and post pics too.

I just did this last week for the first time based on a thread I saw in 'General' by BV Motorsports.
I got a pretty good handfull of leaves and car lint dust bunnies.

Tomo is our local North Texas Fiero Club meet and I plan on showing others there.
This is a fantastic tip.

Thanks again for these pics. My Fiero sat for ten years and had many snake skins and mouse nests (and pounds of turds) throughout the car and, even after driving about 4,000 miles since I got back on the road with it, I had the same smoke cloud described at the beginning of this thread. It doesn't seem urgent, but I want that stuff out of there. It looks easy enough to do myself, too!

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I'm certainly no mechanic, but I have a bunch of pictures of my 86 GT in various stages of it's revival at here. Please stop by and post a comment!

quote Originally posted by blakeinspace: I just did this last week for the first time based on a thread I saw in 'General' by BV Motorsports. I got a pretty good handfull of leaves and car lint dust bunnies. Tomo is our local North Texas Fiero Club meet and I plan on showing others there. This is a fantastic tip.

Not only did I clean the coils but dug out handfuls of stinky debris (can you say mold allergies?) and shop-vac'd the rest.

about that resistor:
i've never owned a 4cyl fiero yet but id like the specifics on that component
--is its a plain resistor or a potentiometer?
--how many leads does it have?
--what is the resistance value(s)?

being a bench tech, i like the challenge of finding a better & safer component that exceeds the oem resistor? specs...i guess im just a geek who likes reading & analyzing electronic schematics.

Something to put on the need to check list.
I've seen alot of honda's with smoke coming out of the dash vents so its not just Fieros.

quote Originally posted by birdpoo: about that resistor: i've never owned a 4cyl fiero yet but id like the specifics on that component --is its a plain resistor or a potentiometer? --how many leads does it have? --what is the resistance value(s)? being a bench tech, i like the challenge of finding a better & safer component that exceeds the oem resistor? specs...i guess im just a geek who likes reading & analyzing electronic schematics.

These are plain resisters in the form of coiled wires. not a potentiometer. looks like three wires from the pic. there appears to be four seperate resistors but I am not sure how they work together. these will be in all fieros, not just 4cyl ones and many many other cars.

Mice will find there way into the heater ducts also. My 86 GT had a nest in the heater fan cage. It was quite nasty and had a couple of little skeletons in the nest. Found another nest right up around the resistors. That's one of the first things I check anymore. Have to do it every Spring when I get the cars out for the summer. Haven't had a problem since I started using the moth cakes and drier sheets.

Dave

ahh, i see said the blind man...i had the 4 cylinder fan resistor in mind confused with the blower fan resistor, which i know are all included to fieros.

technically if the pic above is indeed the blower resistor, and having looked up the blower fan schematic, the blower resistor is a voltage divider circuit. it consists of 2 resistors in series.

the modes of the blower fan switch are dictated by the voltage divider circuit commanded by the HVAC fan switch:
LO---current passes through both resistors. (100% heat load on blower resistor unit)
MID--current passes between the resistors. (50% heat load to blower resistor unit)
HI--current passes through None none of the resistors(straight to GND). (0% or no heat effect to blower resistor unit).

so, from the pic above it almosts look like a T0-3 transistor casing. perhaps the r&d engineers sitting behind their desks did not account for dried leaves, rodent nestings, or dried out lost 100 dollar bills...
the heat problem may be simply solved by installing a custom heatsink. if i had the resistance values of that voltage divider circuit & the amperage draw of the motor, a calculated customized heatsink can be attached to the "blower resistor" to desipate the evil, evil heat....

the possibilites are endless in choosing a heatsink. --e.g. liquid cooled or peltier type,
an old small stereo car amplifier can be gutted out and its chassis used as the heatsink..etc

[This message has been edited by birdpoo (edited 10-18-2004).]

Couldn't you use big high watt sand resistors, or a PWM setup like overclockers use to slow down their computer fans?

Steve

can you get to the heater ducts by just taking out that fan motor?
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'86 Fiero GT

My Fiero XoticRydz
Mid-Rear Madness

[This message has been edited by TaurusThug (edited 10-19-2004).]

quote Couldn't you use big high watt sand resistors, or a PWM setup like overclockers use to slow down their computer fans? Steve

actually i have these wirewound high wattage resistors in mind:

the top resistor is heatsink mountable, can contain two resistors or 4 leads, and can handle up to 200W or 4000V.
the bottom is also heatsink mountable can handle up to 1000W, but 2 are needed to create a voltage divider circuit.

the small chassis heatsink cases such as a car dc to ac converter (inverter) seem to be a perfect candidate for the "blower resistor" circuit.
if i were to design such a circuit i would install the male spades so that the existing fiero blower resistor connector can connect to it.

quote Originally posted by TaurusThug: can you get to the heater ducts by just taking out that fan motor?

Yes, That's what I do. Then you can reach up thru the hole and dig it out of there. And you can stick a vacuum cleaner up into the hole and suck it all out. Does a great job.

I think the leaves get into there around the opening cut for the hood latch, the rest of the area is screened in.

Max

The last Fiero I bought started spitting sparks out of the heat vents on the way home with it. Thank goodness I had just bought a 40 oz soda.
The heat problem can be greater on salt belt cars. Salt spray will enter the fresh air intake and cause corrosion on the coil attachment points.