Voltage Regulator, Bosch - E82 128i, E9X 328i/335i, E60 528i/535i, X3, X5 3.0si
The most-common failure on an alternator can be replaced on its own. OEM Bosch replacement for BMW part #12317561939.
On E82 128i, E9X 328i/335i, E60 528i/535i, X3, X5 3.0si models, electrical and charging issues are not always a "bad alternator". The voltage regulator on your N52 and N54 engine is located on the back of the Bosch 180A alternator and it regulates the output voltage produced by the alternator. A bad voltage regulator can fail to charge the battery at a sufficient rate (slow drain) and it can also allow too much voltage to enter back into the rest of the electrical system where it may damage voltage-sensitive components. Rebuilt alternators will include a new, or tested and approved, voltage regulator. But if you believe the alternator is good, the regulator can be replaced on its own to avoid a bigger repair bill.
Voltage regulators often vary by alternator brand and output. This one replaces the regulator on Bosch 180A alternators used in the models below.
This is an OEM voltage regulator manufactured by Bosch - the original supplier to BMW for this part, as well as many other electrical components. As the OEM it meets all of BMW's original design, fitment, and performance requirements and is TUV approved. OEM parts are the best alternative to more expensive Original BMW parts because they are virtually identical without the inflated price tag. This part has a two year warranty.
Please note: Electrical items are non-returnable. This is standard policy for all auto parts companies. If a new regulator does not fix your charging issue, it cannot be returned.
E82 / E88 (08-13) > 128i
E82 / E88 (08-13) > 135i
E82 / E88 (08-13) > 1M (11-12)
E90 / E91 / E92 / E93 (06-13) > 328i
E90 / E91 / E92 / E93 (06-13) > 328xi
E90 / E91 / E92 / E93 (06-13) > 335i
E90 / E91 / E92 / E93 (06-13) > 335is
E90 / E91 / E92 / E93 (06-13) > 335xi
E60 / E61 (04-10) > 528i
E60 / E61 (04-10) > 528xi
E60 / E61 (04-10) > 535i
E60 / E61 (04-10) > 535xi
E83 X3 (04-10) > X3 3.0si N52 (2007-2010)
E70 X5 (07-13) > X5 3.0si