Fan works intermittenly

scottevest

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After getting the knobs replaced recently on my AC unit, the other fan seems to work differently and intermittently at best, and I can't figure it out.

I recently had the knobs replaced on my AC, both fan strength and coldness. They were loose and needed to be replaced I was told. It seem that these were fixed fine, although it seems to really kick in only once all the way turned, as it should I suppose, but I thought it would be much more incremental. In any event, seems that AC is fine, and blowing from the vents above.

However, now, and I'm not sure if related or not, the normal fan seems to be working much differently from before. If I recall correctly, the normal fan would blow from the center console if I had the vent on, and would blow harder as I moved the fan lever over to the right. But now, it seems that the center counsel only provides air as a vent, with no fan, unless the AC is on. When the fan is turned on, it will sometimes blow heat/cold air to the floor or windshield and more air if pushed to the right. However, I have noticed that sometimes the fan works while other times it does not appear to work, which makes no sense whatsoever to me.

So, my questions are:

-should the fan operate for the center counsel, separate from the AC fan?
-has anyone had problems with the fan for defog and floor working intermittently?

Completely unrelated I hope, I noticed that several of the "plugs" for lack of a better term, near and around the battery have nothing attached to them. I'm not sure if this is important. I will snap a picture.

Otherwise, besides a fairly short list of minor fixes, e.g. can't lock/unlock passenger door with key, door is not shutting properly, it is running great and no longer smoking or losing coolant.

The car is running 1000x better than it was last summer. I can easily redline it and it sounds/feels great all the way to redline. A blast to drive, and feels quite quick. No real complaints.

Scott
 
The vent fan should be all the way off to the left when using the a/c otherwise warm air will be coming into the cabin. If the vent fan only works when your a/c fan is on then something is wired incorrectly. Are you sure it didnt do this before and are now just noticing it? Replacing knobs shouldn't affect any wiring between the 2 fans.

The reason your a/c fan doesn't work until all the way clockwise is probaly because the reostat part is dirty or broken. If just dirty it can be cleaned like mine was:

http://www.e9coupe.com/forum/showthread.php?t=6903&highlight=switch

The temp control switch sensitivity can be adjusted via the hex screw on the back, see at the end of this post under "Update - temperature thermostat adjustment "

http://www.e9coupe.com/forum/showthread.php?t=9633&highlight=clean+conditioning+switch
 
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The two fans

share a common electrical connection. But there is a relay to prevent the heater fan from operating only when the a/c is working.

My personal view is to check the fan motor wiring at the motor first if the slow or medium isn't working. If the rheostat/ speed selection is working you'll get voltage on the wire to the motor under the hood- six or so screws, three under the weatherstriping, small bolts.

The bearings and brushes are exposed with only the rain shield to shield the motor. And the brushes are usually stuck.

I've repaired two by cutting down VW starter brushes. New motors were available from Mesa, perhaps others for ref.
 
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