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Heater.. again

jessicabritt07

jessicabritt07

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Silverton Oregon
Very annoyed at this point.. So when I bought my '81 the heater and a/c didn't work. So my ex and his dad hooked the heater up to a toggle switch, because the heater moter works, just something isnt working in the switch, and now the toggle switch isnt working for the second time. last time it was the fuse. I am pretty sure thats what it is this time too but i didnt check since its dark outside. I dont know what would be making fuses blow so easily since we just put that fuse in there like maybe a month ago... any thoughts? or any thoughts on just how to fix the heater so the actual heater switch in the cab works? :confused:
 
The resistor between the switch and motor may be all thats bad with the factory wiring. I think its mounted in the heaterbox under the hood. I'll try and find a pic

Edit: Should look something like one of these. This is what orilleys site came up with

20083.jpg

ru1320_1.jpg
 
Change the heater motor. It's drawing too much current and is burning out your fuses. Also change the heater motor resistor / relay while you are in there and put a factory switch back in. You'll then have speeds too!:waytogo:
 
k

alrighty. i will pobably be able to go get those next week. I will definitely need help when it comes to install. the guy who had the k5 before me did a number on it. i can post pics tomorrow... :doah:
 
Couple of points:

That resistor is air cooled. DO NOT run the fan without it mounted in the air box. It has to have the fan blowing on it or it will burn out.

Also, you might consider pulling and checking the fan motor before buying a new one.
Dirt, leaves, rats nest, lots of things might be stuck in the fan blade or wrapped around it causing the motor to draw too much current.

Also, most of those use sleeve bearings. If you spin the blade and it stops as soon as you let go, then a small amount of oil make give you a few months to years of use before you have to replace it.

And make sure they used the right size fuse and the wire is large enough. If the wire is too small, it will probably look partially melted.
 
my guess is its electrical, and the blower probably works fine. Those resistors are common to go in all chevy's.
 
Not sure what size fuse Was used stock but in thinking 15amp. Not sure what fuse you Have on your Rigged system but maybe try a next bigger fuse or a circuit breaker so you can reset it and not have to replace It every Time. It
Blows the fuse if it draws too much power or is shorted out somewhere.
 
GM heater motors dont fail that often,the few I've had issues with were mostly due to the bushings on the motor going dry and they would make a drag on it,draw too much current and pop a fuse once in a while...along with making a horrendous screech owl noise at times that sends chills up your spine..I drilled a teeny hole in the bushing at the end of the motor and I'd squirt some light oil in there every fall and that cures it temporarily...

The motor needs a good ground as well as power to work,so if its not getting a good connection to ground it'll work intermittently and could cause the fuse to pop...the resistor gives the multiple speeds,but isn't a must,I have hot wired many heater motors with toggle switches and just had high speed and off and didn't really miss having the lower speeds...

You may want to pull the motor right out,and inspect the inside of the heater box,it might be full of mouse nests and tirds,or have a pencil or something that fell down the defroster ducts interfereing with the blower wheel,which will pop the fuse...inhaling mouse droppings aint the healthiest thing for you either!...almost every vehicle I've owned that sat idle more than a few weeks had mice in the heater boxes...one was so full of shelled nuts the heater motor could not even spin and it kept popping fuses...found several dead mouse skeletons inside the housing,had to use bleach to disinfect it,along with Lysol...
 
If that toggle switch isn't wired up with a relay, it's probably not adequate for the job it is being asked to do, and is heating up from use, blowing the fuse. Do not "upsize" the fuse. The "high" fan setting draws enough to melt the wiring connectors that were used in some applications.

Not a good idea IMO.

The system is very simple, I think the guys are on it with the resistors. The heater switch itself can die (they are replaceable) but that isn't as common as the resistor(s going.
 
Alright

Here's a pic of the motor.... Not sure why there is foam there next to it. And where is the resistor located and is it easy to replace?

image.jpg
 
Replace the whole motor. They are like $20 and all you gotta do is pry the fan wheel off the old one and push it on this one.

Takes like 5 small screws to get the motor out.


I got tired of having to beat mine with a hammer to get the fan spinning lol
 
Resistor "pack" will be to the right of the motor as shown in that picture. The metal terminals (as shown in post 2 above) will be what you see, the assembly is held in by two screws.

I assume if bad, the resistors will be melted in half, but I haven't had that problem on my rigs.

I'm not sure what is up with that fan motor, it LOOKS like a non-AC heater box, but the motor is definitely for AC or Heavy Duty heater, and the vent hose doesn't look like it's going the right way for either of those setups, if I'm correct in that the picture is taken rearward towards the firewall, and the top of the picture is "up".
 
ugh

soo i went to go check the fuse that my ex changed last time, which was the pwr accy fuse cause thats what he hooked the toggle switch up to and the fuse was fine but the port where the fuse went looked all melted inside.... and the fuse wouldnt go back in. not sure what to think about that, so no heat for me until i can replace the heater motor next week :(
hopefully that fixes the problem.
 
Again, I don't own one, but everybody seems to say its to the right of the motor. All you will see is a molex plug with three or four wires that seem to be plugged right into the side of the airbox.
There will be a small raised section under that plug held on with two screws probably.
 
That's it. The silver "box" just down and to the right is the relay, I believe that is for the "high" setting of the fan since you have AC.
 
I have a similar problem blowing fuses, I have a/c and after working fine, it started blowing fuses. But it blows the fuse with the blower motor and switch disconnected. I tried to look for chaffing but I couldnt tell where the wires went through the firewall. Is there anything else that I should be looking for?

Well after digging through the dash for a while, I found a second plug above the blower switch. It controls the a/c I think, unplugged it and no blown fuses! Now to find a replacement switch...
 
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