E46 Alternator Problem
 

I have a 1999 BMW 323i E46 and the alternator is not charging and I am getting the battery light and check engine light on dash. I am not a mechanic but have gone through the following steps and still have not found the problem with alternator.
1) Replaced battery with new battery
2) Removed Alternator and had it tested 3 times and test all came back good. I believe on the test it showed 14.4V
3) Check voltage at battery, jump box under the hood and red wire going to back of battery with car not running and all were same (12+V)
4) Installed new drive belt, new tensioner pulley and new idler pulley
5) Still not charging. With car running I checked voltage at back of alternator, jump box and battery and they were showing below 12V. I assume it was below 12 because car was running on battery only.
6)Checked grounding on car - I assume it is the main grounding wire is the one that I found on the passenger side front near a front sway bar? I removed the ground wire and cleaned it and also had it checked at auto parts and they said it was good.
7) Checked all fuses in the fuse box in the glove box.

At this point I really do not know what else to check. If any one has any ideas please let me know. Thank you and I appreciate your support.

The voltage regulator is installed in the alternator and I dont think it is considered a replaceable part.

When the alternator is tested the voltage regulator is tested as well since it is integrated.

I think the alternator test equipment is at fault and would have it tested elsewhere.

Jeron - Thank you for your feedback. The 3 test that I had run on the alternator were actually at different auto parts stores (Advance, AutoZone and O'Reilly). All showed the alternator as good. Not sure if any of these readings help but I put a volt meter on the car and with battery off I got the following:
Battery 12.42
Jump Box under Hood 12.42
Alternator red cable that bolts on 12.42

With the Ignition Switch Turned On (but engine not running) I got the following on the plug that plugs into to alternator:
Alternator Plug-In Middle Pin 11.00
Alternator Plug In – Outside Pin 11.98

When car is running the volts drop due to the alternator not putting out a charge.

I appreciate any advice that anyone can offer. Thank You.

Just turning the key to ON should not drop the voltage that much.

Do these numbers drop when the key is ON but engine is OFF?
Battery 12.42
Jump Box under Hood 12.42
Alternator red cable that bolts on 12.42

Do the readings at the alternator change when the cables are disconnected/connected to the alternator?

I redid the test as follows. I tried running the car this afternoon for a couple minutes in driveway and it depleted the battery and would not restart. This evening I charged the battery a little using jumper cables and another car to charge it. Also note that when my ignition switch is on my driving headlights low beam are on.

Voltage Test - Ignition Off
Battery 12.22
Jump Box Red Wire 12.22
Alternator Red Cable that bolts On = 12.22
Alternator Plug-In Middle Pin = 0
Alntenator Plug-In Pin on Edge = 0


Voltage Test - Ignition On (Engine not running)
Battery 11.88
Jump Box Red Wire 11.88
Alternator Red Cable that bolts On = 11.88
Alternator Plug-In Middle Pin = 10.78
Alntenator Plug-In Pin on Edge = 11.76


Thank you again for all your help.

I'm having this problem too...3rd new alt.....battery.. checked all grounds and still not getting power .....please help!!!!

Does anyone have any ideas on this charging problem?

Looks like bkirby is having the same problem as mine and I still have not been able to get my charging problem resolved yet.

I appreciate any advice on what to look for or things to check.

Thanks.

You might want to take a look at this articles:

Pelican BMW Technical Article - Alternator Replacement - BMW 325i (2001-2005), BMW 325Xi (2001-2005), BMW 325Ci (2001-2006), BMW 325ti (2001-2004)

http://www.pelicanparts.com/BMW/techarticles/101-Projects-89-Alternator/101-Projects-89-Alternator.htm

These may help answer some questions you have in regards to trouble shooting your alternator issue. If not you can post a comment and I am sure a technician may be able to better assist you with your issue.