Fan Blower problems

[///Sniper535]

I'm having intermittent issues with my fan blower speeds. Most cold mornings my fan does not work at all. I jsut get a slight breeze coming out of the vents on all settings. while driving, it sometime sjust kicks on, then sometimes kicks out and stops working. I have an 02/89 production 535i. also, sometimes when it's on the fan makes a wierd hum noise, could be becuse of the cold weather? So anyways, rebuild or get new sword? or is it something else?

Thanks.

[Sixdown]

I'm having intermittent issues with my fan blower speeds. Most cold mornings my fan does not work at all. I jsut get a slight breeze coming out of the vents on all settings. while driving, it sometime sjust kicks on, then sometimes kicks out and stops working. I have an 02/89 production 535i. also, sometimes when it's on the fan makes a wierd hum noise, could be becuse of the cold weather? So anyways, rebuild or get new sword? or is it something else?

Thanks.

That sounds very much like a sword problem. Extreme cold can crack soldered areas and show brittleness. Rebuilt one is cheaper and if done correctly will last longer than a used one. If the sword is damaged, the wrong and intermittent voltages being fed to the fan motor can cause weird noises.

[Kibokojoe]

Fix the sword, I rebuilt mine for under $10 USD. Not to tough to do either. BUZ71A MOSFETS are cheap
http://www.bmwe34.net/Wiki/tiki-index.php?page=Fan+Blower+and+Sword

Do a google search on sword bmw repair

[Kibokojoe]

Here is a how to that is really good

http://www.bimmerboard.com/forums/posts/355700/

[///Sniper535]

So does an 02/89 have a sword and resistor pack or is it just one or the other?

[Kibokojoe]

My 89 535i has the sword, I am sure yours does too

[shogun]

there is either one or the other, because both have the same function.

[Kibokojoe]

So BMW didn't pick specific models and years for sword or resistor?

[shogun]

looks to me they switched on newer models to the resistor, because that is maybe smaller and easier to install, and/or cheaper production cost. Older E34 have swords, then it changed to resistor, all E32 have swords, either from Siemens (mostly in Europe and on E32 w/o AC) or Behr. The Siemens cannot replace a Behr, different shape and different system. The Siemens sword is shorter, but wider compared to the Behr. Very difficult to get a used Siemens, even in Germany.

[Morgenster]

Don't forget the possibility that it's just the fan speed dial itself.

see:

http://www.bimmernut.com/forum/showthread.php?t=35780

[nirvana19]

Could be the dial but my bet is on the sword. Put a used one in about a year and a half ago and that was working fine until a week or two ago. My car is now 2000 miles away from me, but when I last drove it the fan was intermittent. I think the whining sound you describe is also somehow related to the voltage from the sword as I don't hear that on any speed when the sword is functioning properly, but that's all I often hear on any speed when the fan is sort of working.

[Kibokojoe]

Wish I had all of the electronic gizmos for testing the sword. I would create a rebuilding service :). All I know is that it was not that hard to rebuild and it cost under $15.00 USD for everything including the electronic clearcoat spray that is applied after you solder in the parts. When you rebuild the sword you will be installing a more robust mosfet so you should never have another problem with them frying again. Go for it......