Common BMW Issue: No Power Dead Battery

Make: BMW | Model Example: 2016 X3 | Avg. Mileage: 113420 | Job Number: 372188

Repair Issue:

No Power, Dead Battery

Cause:

Known problem with the fan control module, which is incorporated in the auxiliary radiator/condenser fan itself, causing a current draw. Also, the blower speed controller for the heater and A/C fan can cause an abnormal current draw.

Customer Concern:

Parasitic battery draw

Test/Procedure:

1. Load test the battery, and if it is not a sealed type, test specific gravity.
2. If the battery test is good, install either an inductive low-amp clamp on the negative battery cable, or the leads from a digital ammeter between the battery cable and post. If using a digital ammeter, leave the cable attached to the battery post for the time being.
3. If the battery is installed in the trunk, as is the case in most current BMWs, open the trunk and turn the lock to the lock position to simulate the trunk lid has been closed. Make sure the hood and all other doors are closed.
4. Open and close the drivers door, turn on the ignition and turn on and off electrical consumers, such as lights, heater blower and radio.
5. Open and close the drivers door, then lock the doors.
6. Remove the negative battery cable from the post if using a digital ammeter without an amp clamp, leaving the leads connected to the post and cable end. If using a low-amp clamp, leave it connected to the negative cable without removing the cable from the post.
7. Monitor the current draw. After 16 minutes minimum, the current draw reading should be at a nominal level of 50 milliamp or less.
8. Many late model BMWs may take as long as 70 minutes to reach steady state current draw minimum readings.
9. Be sure to disconnect the B+ cable at the alternator as this is also a known draw source.

Tech Tip

Attempting to test current draw on late BMWs without following the above steps can lead to erroneous readings. There is a known problem with the fan control module, which is incorporated in the auxiliary radiator/condenser fan itself, causing a current draw. Also, the blower speed controller for the heater and A/C fan can cause an abnormal current draw.

Important Take-A-Way:

By going the 9 testing steps, automotive mechanics should be able to void spending wasted time chasing down erroneous readings, and be able to focus clearly on the right fix.

Most Popular Fix:

Replaced/Repaired Blower Control Final Stage Unit – Replaced/Recharged/Programmed Battery

Other Common Car Problems:

View more common car problems from the most popular manufactures including Ford, Dodge, Chevrolet, Honda, Toyota, and more. Read more

Also applies to the following Makes and Models:

2008 128i 3.0, 2000 323CI 2.5, 1999 323i 2.5, 1999 323IC 2.5, 2001 325Ci 2.5, 2002 325Ci 2.5, 2003 325Ci 2.5, 2004 325Ci 2.5, 2005 325Ci 2.5, 2006 325Ci 2.5, 2001 325I 2.5, 2002 325I 2.5, 2003 325I 2.5, 2004 325I 2.5, 2005 325I 2.5, 2006 325i 3.0, 2002 325XI 2.5, 2003 325XI 2.5, 2004 325XI 2.5, 2005 325XI 2.5, 2006 325xi 3.0, 2008 328I 3.0, 2008 328xi 3.0, 2002 330Ci 3.0, 2003 330Ci 3.0, 2004 330Ci 3.0, 2004 330i 3.0, 2005 330i 3.0, 2006 330i 3.0, 2001 330XI 3.0, 2001 525i 2.5, 2002 525i 2.5, 2003 525i 2.5, 2004 525i 2.5, 2005 525i 2.5, 2006 525I 3.0, 2006 525xi 3.0, 2007 525xi 3.0, 2012 528i 2.0, 1997 528i 2.8, 1998 528i 2.8, 1999 528i 2.8, 2000 528i 2.8, 2012 528i xDrive 2.0, 1999 528IT 2.8, 2000 528IT 2.8, 2001 530i 3.0, 2002 530i 3.0, 2003 530i 3.0, 2004 530i 3.0, 2006 530XI 3.0, 2000 540i 4.4, 2000 540IT 4.4, 2004 545i 4.4, 2005 545i 4.4, 2004 645Ci 4.4, 2005 645Ci 4.4, 2006 650i 4.8, 1997 740I 4.4, 1998 740I 4.4, 1999 740I 4.4, 1998 740iL 4.4, 1999 740iL 4.4, 2000 740iL 4.4, 2001 740iL 4.4, 2002 745i 4.4, 2002 745LI 4.4, 2003 745LI 4.4, 2004 745LI 4.4, 2005 745LI 4.4, 2007 750Li 4.8, 2008 750Li 4.8, 2003 M3 3.2, 2001 M5 5.0, 2002 M5 5.0, 2003 M5 5.0, 2004 M5 5.0, 2005 M5 5.0, 2006 M5 5.0, 2007 M5 5.0, 2008 M5 5.0, 2017 X3 2.0, 2004 X3 2.5, 2005 X3 2.5, 2004 X3 3.0, 2005 X3 3.0, 2006 X3 3.0, 2007 X3 3.0, 2001 X5 3.0, 2002 X5 3.0, 2003 X5 3.0, 2004 X5 3.0, 2005 X5 3.0, 2001 X5 4.4, 2002 X5 4.4, 2003 X5 4.4, 2004 X5 4.4, 2005 X5 4.4, 1996 Z3 1.9, 1997 Z3 1.9, 1998 Z3 1.9, 2001 Z3 2.5, 1997 Z3 2.8, 2003 Z4 3.0, 2004 Z4 3.0, 2005 Z4 3.0, 2006 Z4 3.0

Author: Anthony Zaro

Anthony attended the Dunwoody College of Technology Automotive program from 2007 to 2009.He worked at two dealerships in the Twin Cities before coming to Identifix. Anthony is an L1 certified Master Technician. He enjoys playing video games, lifting weights, and playing guitar. Anthony’s number 1 priority is his daughter.

Our database continues to grow! Our professional auto repair technicians add new fixes submitted by our Direct-Hit® users. These case studies are confirmed, experience-based fixes directly from technicians and shops. You can find these solutions and more in Direct-Hit®.

Learn more about Direct-Hit® today!