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Bosch Voltage Regulator | 30097

Audi, BMW, Mercedes, Porsche
In Stock Status
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Leaves warehouse within 1-2 business days.

Make Sure It Fits

P/N: 30097 Bosch OEM
Please verify Bosch number (Long number 1197311027 or 1197311035) on existing regulator assembly prior to ordering. 1 per car.
Cross References:
  • 0021547906
  • 034903803
  • 1197311027
  • 1197311035
  • 12311726022
  • 1987237059
  • 70443011101
  • W01331629632

Voltage regulators maintain a constant range of alternator voltage output and convert the alternate current (AC) produced by the alternator into the direct current (DC) the vehicle operates on. As the alternator turns, it uses coil windings and magnets to create the alternate current. The faster the alternator turns, the more current and voltage is produced. The voltage regulator uses diodes to convert the AC to DC, limiting the alternator's voltage output to 12-14 volts.

Voltage regulators fail when they can no longer convert alternate current to direct current or when they can no longer maintain a consistent voltage that the vehicle requires to operate.

Signs of a faulty voltage regulator include:
  • Surging lights
  • Flickering interior lights
  • Instrument cluster or panel malfunctioning
  • Battery light or check engine light illuminated
  • A battery not being charged

Checking battery voltage or alternator output are simple ways to test a voltage regulator. Fluctuating battery voltage or drops in alternator output when the engine is at idle indicates the voltage regulator has failed and is not regulating voltage or not converting alternate current to direct current.

Replacing Your Vehicle's Voltage Regulator

Some voltage regulators are external to the alternator and can be removed and replaced in series with the alternator output circuit. Other voltage regulators are mounted inside of the alternator and may be removable and replaceable, but some will require the replacement of the alternator to replace the voltage regulator.

View more Bosch Voltage Regulators.

Bosch is the world's largest supplier of components to the automotive industry. The Bosch product line includes alternators & starters, brakes, electronic controls and sensors, fuel system parts and management, ignition system components, and steering system components. All Bosch automotive parts are either OEM (Original Equipment Manufacturer) or made to their specs as a replacement part for the OEM unit.
Left = Driver side and Right = Passenger side.
All parts are priced individually unless identified as a set or kit. "Per car" notes identify how many of a given part your car has and "Left/Right or Front/Rear" notes means the part fits the left or right side of the car. These parts are still sold individually and you'll need to select the appropriate quantity if you plan to replace more than one of this item.

Frequently Viewed Together

We found 10 additional part(s) that are frequently viewed together.

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What This Bosch Voltage Regulator Fits?

Application information below is for reference only and should not be used to determine the exact vehicle fitment. Please use the "Make Sure It Fits" vehicle selection box above to determine the exact fitment and review any application notes. If you need any help determining if this part works with your vehicle, please don't hesitate to contact us.

89-91 - 100 Base, E
89-91 - 100 Quattro
92-94 - 100 Quattro CS
110 Amp.
89-91 - 200
89-91 - 200 Quattro
87-88 - 5000 S
For models with chassis serial number from 081501.
87-88 - 5000 Quattro S
91-92 - 80
88-92 - 80 Quattro
88-91 - 90
88-91 - 90 Quattro Base, 20v
90-91 - Coupe Quattro
94-94 - S4
110 Amp.
90-91 - V8 Quattro
For models with chassis serial number through 000609.
88-95 - 750iL
# 0 120 468 072 Applies to Bosch 140 Amp. Alternator # 0 120 468 033; Manufacturer Body Code: E32
93-94 - 850Ci
94-95 - 850CSi
91-92 - 850i
92-93 - 300SD
For models with chassis serial number through 002386.
90-93 - 300SL
For models with chassis serial number through 10-001590(M/T) or 12-014273(A/T).
90-92 - 500SL
95-96 - 911 Carrera, Carrera 4, Carrera 4S, Targa, Turbo
89-93 - 911 Carrera, Carrera 2, Carrera 4, RS America, Speedster & more
Manufacturer Body Code: 964
94-94 - 911 Carrera 2, Carrera 4, RS America, Speedster, Turbo 3.6
Manufacturer Body Code: 964
Manufacturer Body Code: 993
97-98 - 911 Carrera, Carrera 4, Carrera 4S, Targa, Turbo
Manufacturer Body Code: 993
82-88 - 924 Base, S, Turbo
85-95 - 928 GT, GTS, S, S4
83-91 - 944 Base, S2, Turbo
87-90 - 944 Base, S, S2, Turbo
92-95 - 968