Fan won't stop

[gearheaddc]

I need a little help. I have a 1999 323ti. I was driving down the road and heard a high pitched noise that I'm not used to. It sounded like some kind of an electric motor running. I turned the car off and the sound gets lower in pitch but keeps making noise. I pop the hood and I find that the noise is coming from a unit the is just to the left of the engine and behind the shock tower. You can see it in this picture:
http://www.bimmerdiy.com/diy/e36coolingsystem/Rags.jpg
It's the unit with the hose coming towards the front of the car. I know this isn't something I usually hear so I drove the car home and unplugged the battery. First I'd like to know what that unit is and if anyone has had this problem before. Any help would be appreciated.

[CrazyCoder]

Secondary Air pump!

Search for it, if it's making noise now, it's on it's way to air pump heaven.

[gearheaddc]

thanks crazy coder, sounds like mine is struggling. I'm just wondering if it's normal for it to keep running when I turn the car off. I had the key out of the ignition and the whining still kept going. Should I have been more patient before disconnecting the battery?

[CrazyCoder]

thanks crazy coder, sounds like mine is struggling. I'm just wondering if it's normal for it to keep running when I turn the car off. I had the key out of the ignition and the whining still kept going. Should I have been more patient before disconnecting the battery?

Mine does it too, but it should shut off in less than a minute. It should only really run when the car is cold.

[gearheaddc]

Well, I went back downstairs and reconnected the battery. The fan turned on right away but I figured I'd take it for a drive and see what happens when I take it to operating temp. The fan never turned off. I drove around for a while and then decided to park it. I ended up disconnecting it again. Maybe some relay or sensor problem???

[CrazyCoder]

Could be a relay, I don't have my Bentley handy (at work).

Hopefully someone will chime in with some input who knows about this, but there was also a post a while back that had a link to a downloadable Bentley manual.

You could always just disconnect the pump, it'll throw a CEL, but it won't hurt anything other than that.

[gearheaddc]

bump

[gearheaddc]

bump