My 87 GT had a small fire in the evaporator core due to the blower motor resistor igniting what apparently was a mouse nest. I discovered this when I was changing the evaporator core last summer after pulling it out of storage. Luckily, the fire flamed out quickly and didn't burn the car or the house down, but it was a fire nonetheless, and it was hot enough for long enough that it melted the evaporator core cover, making a quarter size hole in the bottom of the cover. So this year, I've asked the storage facility to unplug the resistor before starting the car, so I can get it home and scope the evaporator core area with a camera. My stupid questions are as follows:
1.) Will this cause any problems that would make you NOT unplug the resistor prior to driving it home?
2.) What does the resistor control? Fan speed only? Are there other functions that need this resistor?
3.) While the resistor is unplugged, I simply won't have a functioning blower motor, correct? But I will still be able to heat the interior just from "blow by" through the vents, right?
Sorry for the elementary questions, but I just want to make sure that I don't do something with the best of intentions, and really screw myself.
1.) Will this cause any problems that would make you NOT unplug the resistor prior to driving it home?
It will work, but it's not necessary. If the heater is off, the resistor will not get hot.
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2.) What does the resistor control? Fan speed only? Are there other functions that need this resistor?
Fan speed only...and only the lower speeds. The high speed does not use the resistor.
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3.) While the resistor is unplugged, I simply won't have a functioning blower motor, correct? But I will still be able to heat the interior just from "blow by" through the vents, right?
There would be no air movement through the heater core...it will not heat the interior.
[This message has been edited by Gall757 (edited 05-06-2020).]
You can disconnect the heater fan resistor plug when it is stored.....Before driving it, simply pull the resistor pack out and look inside. If you see anything then drive home with it unplugged.
I actually am curious about how mice can get in there; Do they only come in thru the vent at the base of the windshield or can they climb in thru the water drains? I have personally never experienced this problem- My car was parked outside for it's first 20 years but since has been in the garage. The foam around my hood latch is intact....that was the only place I could see them getting in......
I usually clean the mice out by pulling out the blower assembly. But on my car they get in because the grill at the base of the windshield doesn't always sit flat and there are gaps too. So they can squirm in there. I have a small chunk of mouse poison in the front trunk. They go in there first because they can smell the poison. There is a gap in the otherwise pristine front trunk rubber seal. They get in to the trunk that way. The poison keeps them out, no more nests now.
------------------ 86 GT built 2.2 ecotec turbo rear SLA suspension QA1 coilovers on tube arms
Gall757, wouldn't the mixer door still operate? If it does, there may be some air flow through when the car is moving and the Vent button is activated.
If the cowl vent cover isn't warped, about the only place mice can get into the hvac ductwork is through the drain hoses on each side. Even with a car that's a daily driver, small leaves, tassels from trees and the like can pass between the windshield and the cowl cover and make their way into the ductwork. From time to time, I have Maple seeds, pine tree tassles and needles and some small leaves that will pop out of my dash vents. It's a good idea to make it a yearly thing to clean out the fan cage and the resistor pack area.
3.) While the resistor is unplugged, I simply won't have a functioning blower motor, correct? But I will still be able to heat the interior just from "blow by" through the vents, right?
The resistors slow the fan speed at other than high speed setting; the top speed should still function. If the fan is off, the designed air exchange will occur when the car is moving, so heat will enter the cabin.
[This message has been edited by David Hambleton (edited 05-06-2020).]
Gall757, wouldn't the mixer door still operate? If it does, there may be some air flow through when the car is moving and the Vent button is activated.
Yeah...some air flow would happen with the car in motion; probably need to get up to about 85mph tho... Using the high position on the fan knob would work better (with no resistors operating).
You don't actually put you face is there but any smallish camera will show you.
If have mice... Do Not use a vacuum cleaner. Not even ones claiming has "HEPA" filters. Wear gloves and clean carefully so you does get mice crap etc in the air and contaminate a garage or worse a house. Put this trash in own bag too. Mice et al carry germs that can kill you way before CCPvirus currently making problems. Often this can depend just where you live but most can tell so just be careful.
------------------ 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)
I can see a nest under the mesh in the my Wiper Cowell. I am going to remove the Cowell, Blower, and Resistor, clean it all out then put 1/4 inch steel mesh over the air input port so mice can't get into the HVAC system. Then, under the car where the windshield drains empty out, I am putting steel mesh over those openings to keep mice out of the tubes. My mechanic will clean them during my yearly state vehicle inspection. I put mesh over the coil and alternator cooling tube outlets and on the associative fan inlet port in the frame (located inside the rear trunk). I also took out the trunk liner and put mesh over all the frame holes in the trunk area just in case. I also have mesh inside the air intake scoop that I check weekly. I am going to put mesh bent into a lazy L shape around the front and rear trunk seals that just touch the lids when closed - making an outter fence around the rubber seals to keep mice away from them. I put removable mesh around the air cleaner to wheel well fire wall area to keep mice from making nests there - they like that cozy spot - ate through my IAT Senor wires but I now have steel braid over those wires. Mice get under my doors and hang out in that long/flat/tight area but they don't get in the car. I made winter door jam rubber seals that I tuck into the all the gaps on both doors and I made wire mesh covers (coated in thick rubber paint) that go over the side mirrors. Mice can now only get into the engine compartment and front area around the lights and radiator. Checking them is now simply lifing both hoods and a visual inspection without needing to remove anything (except anything mice have left behind). Keeping mice out of the cabin is paramount.
Next year I am building a 1/4 inch steel mesh cage for my Fiero just like the one that I built for my Benz. It works great, I have cameras on it, mice can't get/chew through the mesh or crawl under the cage frame, only baby garden snakes can get in but they stay on the floor. It only takes 5 minutes to dismantle the cage with 16 wing nuts. I will post photos if anyone want to see what I did to keep mice out 100% during the winter storage.
------------------ Paul Romsky
[This message has been edited by Romsk (edited 11-30-2022).]
Might keep mice out but will plug w/ crap and water can flood the car. Because a lot of rain and snow flows down over windshield faster that partly or completely plug drains handle. Then the sump fills and water goes into the heat air intake.
Cowell have screens but still have holes big enough to let crap in the sump. Broken Leaves , pine needles, and more are sitting in many sumps but drains sit above lowest point so don't plug easy for trash that sinks. Anything floating is down the drains and out of the car. Even still the drains can plug easier for people that park under trees.
adding screen(s) to heat intake often isn't simple... Many put screens and never check wiper parts don't hit and cause wiper problems or motor dies first time driving in the rain. P-side arm and link has low clearance w/ intake parts. And not just a Fiero issue.
[This message has been edited by theogre (edited 12-01-2022).]
You inspired me to make my post: "Mouse Proofing the HVAC System".
I am not sure why GM went with that resistive wire concept. They knew it would get hot and they know mice can get into automotive HVAC systems.
I think it is for feedback to the fan speed controller, sort of like a flow regulator. Current flow though the wire is a function of its temperature. If the air flow is below the set point for the selected fan speed, the wire will get hot, current will change, and the fan will be sped up slightly until speed vs. temperature balances out. It's inexpensive and clever, but if it were me? I would have used a PWM controller for fan speed and not have the fire hazzard of that resistive wire at all.
I am putting 1/4 inch galvanized steel mesh all around my Fiero where mice can get in. This includes the outside air inlet located under the Wiper Cowell and under the car where the Wiper Tray Drain Tubes open out.
TheOgre gives sound advice, but this time I don't fully agree with him. I would rather keep mice out as much as possible (maybe if not even 100% mouse proof - but that is a goal). I can quickly look into the Wiper Cowel to see if it is blocked with leaves and such. And I can use my Inspection Camera to quickly and periodically check that the Wiper Tray Drain Tube outlets under the car are clear. I can also run water onto the Wiper Tray and see how quickly it drains. Since my car is inspected every year for New Hampshire registration renewal, my mechanic will check/clean the mesh if he finds any blockages. This might not work for most people, but since I drive my Fiero only for "fun" occasions, I just added to check the mesh locations to my pre-start check list - its has gotten quite comprehensive over the years. I now plug my engine exhausts with heavy duty stainless steel pot scrubbers (chipmunks stored a whole cache of tiny nuts in there from the ornamental cherry trees in my yard). I even put a red hanging ribbon "REMOVE BEFORE STARTING" on them - much like they put on aircraft: "REMOVE BEFORE FLIGHT". Friends think it is cool.
I think car manufactures pass on putting heavy duty mesh over mouse entry points because they are afraid that owners will not be diligent and check them regularly. They would rather let a mouse tear up the car (and gag the owner with fowel smells) rather than let water leak into the car (which makes sense because leaving a car out in the rain unattended occurs more often than a mouse getting into a car).
Romsk
[This message has been edited by Romsk (edited 12-01-2022).]
Using the high position on the fan knob would work better (with no resistors operating).
