MF 593 cab blower motor lessons learned

[likembikem]

I have learned quite a bit this past week about my MF 593 cab fan blower motor. I didn't get anywhere searching on the internet and people at dealerships were not of much help either. It started with the fan just quit working. I removed the top panel on the roof and found the 3 speed resistor pack had failed. It has 4 wires connected to it, one is hot and the other 3 are each of the 3 speeds coming from the switch in the cab. between the hot wire and the wires going to the speeds (controlled by resistors) is a fuse link. This is only a piece of solder wire, mine had opened up and I thought that was all that was wrong, didn't know that was a fuse at first and just soldered #14 wire across it. Motor was working but I thought why would there be a short between two positive connections, it must be a fuse link. So I got a new resistor pack and the fusable link blew again. This time I soldered an inline fuse holder with 20 amp fuse and ordered a new blower motor. The new (aftermarket) motor squirrel cages would not fit in the slots and I had to carefully move the squirrel cages until there was no interference, there is only about 1/16 inch on either side. Then I put back in my resistor pack with inline fuse tucked out of the way and everthing is working fine. No one knew the resistor pack (speed control) had a built in fuse. Not sure what was wrong with the motor but it was pulling way to much current.

 

[likembikem]

Just to clarify, I looked on the internet for my problem but was not registered here and did not know of all the resourses here. Also an automotive parts dealer ( apparently Dodge trucks use about the same thing) said the resistors do not produce heat, they do. The resistors only add 1 ohm (med)or 2 ohm (low). Some tractors the fan will run on high only if the resistors go out. The fuse link, just solder; come on...how much amps does it take to blow? No dealer I talked to knew it was fused. And lastly; adjusting the plastic squirrel cage fans up and down the shaft to fit in the fan box was a little unnerving, I'm sure if one had broke I would just be out the $220. that's all!