Blower motor-The sequel

[cheapta]

I have a 99 Sierra. I know they have week blower motor resistors,I've read all the posts about it.Here's my problem. I replaced the resistor with an AutoZone piece about a month ago and it lasted about a week. I went to GM and bought another resisitor and was quite surprised to see it was identical to the AZ part-both made in Slovenia. That one lasted about 5 days before it quit.
The original is completely different from both replacements,it's much shorter. When I got the GM piece I had to supply the VIN,I was told there are two different resistors. Am I getting the correct resistor? Is there a relay or something I should be looking at? I'm cold!!
Any help would be greatly appreciated.

[PencilPro]

I would check to see if the blower assm. is clogged with leaves first.
If there isn't enough flow to keep the resistor cool and stopping it from getting overheated.
Another thing is that if it is full of leaves, then they need to be cleaned out before they start to rot your coil.
The only unfortunante thing is that it is hard to get all the leaves out without taking the assm. apart.
The good thing is you won't have to do it again for several years. There is a coil cleaner that you can get at your local AC supply store for homes.
The best I've found is called Coil Blast.
Hope this helps!