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Normal voltage to cigarette lighter engine off is 12.7. Engine on, no accessories, 13.8. With just a/c on, no increase in blower power position, voltage is 13.2. Full a/c blower power voltage drops to 12.6. The battery is now draining. The blower fan needs some attention. It appears difficult, at best, to even access it. The A/c needs some work as well, on a hot day it cannot keep cabin cool. Any clue on how to attack this?

Blower fan shaft bearings may need lubing. If the fan wheels don't spin freely it could explain the overload.
AC - Recharge, leaks etc..?

I removed the stereo and stuff to get to blower. All I was able to see there was a lot of dust. I was able to spin the blower but I was not able to gauge the resistance-compared to what? I know that when wind speed doubles the air resistance quadruples. That would explain the drain at the higher blower settings.

However, the blower and Evaporator are encased in this "plastic suitcase" so there is currently no easy way to access the blower motor or bearings.

Has anybody removed the ac blower? And how did you do it?


http://www.realoem.com/bmw/showparts.d ... g=64&fg=55

I've never done it, but I do have a second blower assembly in my stash and after separating it from the housing and inspecting it on the bench I do believe there is no way to effectively get to the blower without removing the entire assembly from the cabin and separating it from the housing, even though some of it is visible from behind the stereo.

Having said that there is a way, however, to oil the bearings on the blower installed in the car. I've done it successfully several times when it starts skweeeking. In the pics below, notice the tiny hole(s) in the squirrel cage. This one shows two, my original in the car only has one. There are two sets, one set for each side, left and right (and hence the way to get oil to the bearings). You need one of those zoom oilers with the extender spout, then reduce it even further with a WD-40 oiler sticking onto the end. That's the only thing I've found to go through the hole to get to the bearing. What is impossible to photograph is where the actual bearings live on the shaft. They are just about halfway between the two squirrel cages, each side as shown. Spin the cage to position the hole you are going to use for oiling at exactly 12:00 (so the oil will drip down onto the shaft). I push the tube through the hole until it meets resistance and squeeze away, sometimes takes a couple of applications. Hopefully the pics will give you an indication as to what's on the inside that you can't see.

Expounding on what Lenny said, there is felt in a small housing around the shaft/bearings and what you really need to do is to try and saturate the felt, it serves as a reservor for the oil.

I jumped too fast. While that may be a, or the problem, do an amp draw first and see if it's in specs. Seems like the motor draw at high speed is about 7 amps. Don't quote me, but I'm pretty sure... Compare it to the heater blower, I'm told it's the same motor.

Did the Lube suggestion. Other stuff. Unplugged Aux fan- no difference. Did find something interesting. With a/c on and full blower and when the Compressor goes off due to sensor in cabin. Cold blower voltage goes back up to 13.4. Same as warm air blower on full. Something related to compressor.

I am not going through a hot summer without cold a/c!!!