Blower Motor Resistor Pack

[ScottyWM]

OK, I had the classic resistor pack failure mode - fan would intermittently cut off, and only run on speed 4. After about a minute or two, the fan would run on the lower speeds for a while, but them it would cut off again. This repeats over and over. This doesn't happen every day, but it seems to happen most on the hot days (although I seem to remember it happening in the winter a little bit?)

I had the same problem 9 years ago, and diagnosed it as the resistor pack. Replaced it ($11), and everything was fine. So I ordered a new resistor from the same favorite california supply place ($44!), and put it in. What?? The Blower fan is still doing the same thing! Didn't fix it.

Did I get a bad new resistor pack? Or could it be a different problem? Is there a way to test the resistor pack - especially since it is intermittent?

[Bimmer Nut Ed]

I had similar circumstances. Replaced the resistor pack once, then a while later (year or couple years) the blower actually went out. It only ran sporadically, then only on high, and later it cut off all together. I opened up the compartment on the firewall from inside the engine compartment, and turned the blower motor blower wheel, and dang it started to work. I ended up buying a new blower to fix it. Turned out the brushes on the old motor were completely worn. Prolly could have simply fixed it with new brushes, but I just replaced the whole darn thing.

[shogun]

yes, maybe the motor brushes
page_2 (http://www.nmia.com/~dgnrg/page_15.htm)

[ScottyWM]

Well, I was getting the occasional squeaking from the blower motor last winter. I attempted to replace the motor with a junk yard one. I got all the way down to the motor, but could not see how it would possibly come out - there just wasn't room. It looked to me that I would need another 2-3 inches to get the damn thing out! So I simply lubed the bearings and bundled it back up. I could see the brushes and comm were quite worn, but the squeaking stopped and the motor worked after the lube.

I guess you're probably right... I just really don't want to have to try to get that motor out again! And new ones are over $200! The junk yard one I got looks almost as bad as mine. I could replace the brushes and clean up the comm, but it would still have the old bearings and worn comm. I guess this would be a good project for this summer.

When the blower stops, it is almost rhythmic. It will shut off for about 2 minutes, then come back on for about 45 seconds, then off for 2 minutes, repeat... Seems to only do this when it is really hot (over 90degrees), cooler weather it runs fine. This struck me as the resistor heating up and failing, then cooling off over the 2 minutes so it would turn back on, then heat up and fail, etc. I'm not sure a bad motor/brushes would act like this?

Thanks for the input guys.

[Bimmer Nut Ed]

Yeah, mine never turned on and off my itself. When you started the car, it either worked, worked only on high, or did not work at all. And when it did not work at all, a day or so later, it worked again. Mine was the brushes "going out", getting worn out. I figure when it ran only on high, they wore out just that much quicker.

Yeah, the mouse cages are a pain to squeak in and out of that fire wall, but if you take your time, it can be done. I think with mine, I ended up cracking it a little, but not enough to really affect its continued operation once I got it all back together. I think I got it out clean, but putting it in, I was a little impatient! Good luck.

[shogun]

Ross has made a nice instruction how to use a cheaper MB blower motor. He has sent it to me and here we go, see/click Lagergreen
FIXES - CLIMATE (http://twrite.org/shogunnew/fixes/climate.html)

[ScottyWM]

Just wanted to let you know how it turned out. The problem was that the first new resistor pack was defective from the get go. They sent me a new resistor and it works just great. Really need it with the heat we're expecting!