GM Blower

Just in time for you folks like me that live in the "Great White North" and I know a little late for you mountain folk.

After searching for gm fixes on the internet machine, I was disappointed. As we all know jeeps were only made after 76 right! This modify works for the ICJ_ and might work for others but I don't have any others. The project started when I did a full body off rebuild. I went through the heater box not sure if I would even put it on the jeep. I am glad that I did. The nice thing with the jeeps, are the blower comes off in one piece. There are about 3 bolts on the front and 3 around the flange on the top. Once off and in your hand you will see the fan blades come off with a nut. Be careful taking the blades off, you will reuse on the "new" motor. Take the old two speed motor off and make a nice powered pencil sharpener out of it.

On the GM motor you will need to take off the fan blades (if still attached) most likely it will have a 10mm head nut holding the blades on, keep the nut! With the blades off check to make sure there are no washers holding the blower together. If there are gently pry them up evenly on both sides not to deform them too much. Now flip the motor over. You should have 4 finger holes holding the brushes plate to the motor. Gently pry them up to remove the plate. You will then flatten those finger later when the project is almost finished. So make sure you are careful.



With the Brushes cover off you will notice the locations of the Pos and Neg. Now is a good time to mark them. (don’t really need to but later it might come in handy on the next motor) If you notice in my picture, the modify is all ready done, the computer glitched and deleted my org picture, sorry.



Now for the modifications. If you look at the neg brush it is soldered down to the plate. Cut that wire as close to the plate as you can. On the Pos brush I cut in the middle of the brush wire to add butt crimps later. You will need a 6” wire, two but crimps, and a eye crimp, one machine bolt and nut. (unless you solder) I crimped the Pos wire 1st on the side where you attach the wire harness to. Then routed the wire under the brushes plate. This will hopefully keep it from bouncing around much and causing a long term ground issue. Now you add the brush to the other side of the wire and make sure your brush can move in and out freely. On the Neg side I drilled a hole and attached the Eye crimp to brush and attached to make sure it also moved in and out freely. Throw some grease on the bushing and you are set. (it helps to use a bread twisty to hold the brushes back on reassembly as shown in the picture)



With the motor apart it would be a good time to clean and grease.



When reassembling put the brushes plate on the armature 1st then in the magnets last. This will give you a chance to make sure the brushes are where they need to be.

Now gently flatten out the fingers to hold the plate to the motor. Make sure the motor spins freely! If it doesn’t some thing is wrong.



Now on to the Jeep plate. Place the motor over the top. Make sure the plate is centered over the hole, clamp and drill the holes from the GM bolt pattern. If you notice in my pictures it is clocked to the right. Make sure your wire will go that far! Mine has a new wire harness! So it might be different from yours.



Once all the holes are drilled start to add the machine bolts. Drop the bolt through the blower and nut it, put anther nut on, then the jeep plate, then your final nut. (I would use a bigger machine bolt then smaller but doesn’t have to be ¼” just not needle thin)

Make sure the plate has an even distance all the way around. If one side is closer it will cause the blades to spin tilted and chew up blades. If you notice in the picture the blades in the background, mice did a number on it. The blades push a lot of air even it that condition.



Once all the distances have been checked, nuts tightened, checked to make sure everything still free spins, then you can cut the bolts flush. It would help also to paint the unit esp the bolts, it works as a small lock tight.

Put the fan blades on the new motor, put the 10mm nut on to hold the blades on and put whole assembly back in jeep.



Now with the new motor in you will need to decided on how to run the three speeds. I used a new switch from napa that has the resistor built in. Doesn’t look Factory but lights up, one wire, all contained and looks Okay.

As you can see in the picture it doesn’t look completely out of place. With some paint and some creativity you could make it look factory. This is was a quick job to get the basics down. I hope it helps some folks out there!

Just my way of giving back, thanks!

 

thats one for the archives.
good work!

 

Here's another one thats been up for years, and he's a member here also.

http://home.comcast.net/~sday77/binky/index.htm

 

If you reuse the GM fan won't it now be spinning in the wrong direction for the pitch of the blades?

 

You reuse the jeep fan and part of the mod is to reverse the motor for it to work. I have one in the garage I did the winter before last but have never installed it. The website I posted tells you how to reverse the motor.

Edited to clarify!

 

Yes, I understand that the motor needs to spin in the reverse direction, but if it's using the same fan, but now spinning the motor in reverse, won't the fan now be spinning backwards? Squirrel cage fans are designed to work in only one direction.

 

PathKiller

I took the old blades off the Jeep motor, put it on the "new" gm motor. the GM blades I threw away. the Jeep ran CCW from the start. Also the Jeep also uses a D type of hole where the GM is square, Ideally you would fill the rest of the hole. but with mine being used I wanted to be able to replace it later if I had too.

 

Great, thanks. That's what I was wanting to know.

 

Is that a 72-77 Heater Box? How does it work? I tried the dodge d150 blower upgrade and was sorely disappointed...

Clean install though, looks factory.

 

I know it fits all the ICJ5 (6) I don't own anything past 75. From what I have read, if the motor is inside the cab, it works. I was going to make it look extremely factory with some wood blocks cut in circles and painted, etc. but its cold and works fine for now.

 

what gm motor did you use here? Do you happen to have a part number or a vehicle that it came off of? How does this blower compare to the original one? will it actually defrost a frosty windshield?
I really want to do this conversion, do u think you could help me out?

thanks,
nathan