BMW Electrical Sensors, Switches, & Relays for BMW 5 Series E34 (1987-1995)

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Electrical gremlins can be very frustrating. Luckily your BMW's electrical system is better than most, even if it's 25 years old. Here you will find electrical relays, sensors, switches, and modules for the engine, camshaft, and crankshaft. Our parts are OEM, Genuine BMW, or approved aftermarket brands that we have an excellent track record with. There is no middle ground with electrical parts - it either works perfectly or not. And there's nothing more frustrating than a new part that fails right out of the box. So it's important to choose quality replacement parts over a cheap but faulty piece.

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Bavarian Autosport - Corporate Logo
T#:25042544
Part#: 12311744567
Ships in 4 Business Days
Sale - Save 15% $ 219.99

This product was last offered at the strikethrough price on
05-03-2026

$ 186.99 USD
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Sale - Save 15%
$ 219.99

This product was last offered at the strikethrough price on
05-03-2026

$ 186.99 USD
Free Shipping on orders $49 and up
Bavarian Autosport - Corporate Logo
T#:579816
Part#: 52380
In Stock
Sale - Save 20% $ 48.99

This product was last offered at the strikethrough price on
05-03-2026

$ 39.19 USD
Free Shipping on orders $49 and up
Sale - Save 20%
$ 48.99

This product was last offered at the strikethrough price on
05-03-2026

$ 39.19 USD
Free Shipping on orders $49 and up
Common cause of misfires, poor fuel economy, or a crank no start situation. If your M50 or S50 has any of these symptoms, this crankshaft position sensor from Bavarian Autosport is a likely fix.
OEM Bosch Voltage Regulator (Bosch Alternator) - 12311726022 ...
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Bosch - Corporate Logo
T#:19326
Part#: 12311726022
In Stock at Vendor
$ 71.99

This product was last offered at the strikethrough price on
01-28-2026

$ 62.99 USD
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$ 62.99 USD
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This is the voltage regulator found on the back of the alternator. It's a normal wear item and the contacts are the first thing to check if you believe the alternator is not charging the battery (lights flickering or dim, battery light on in the dash, the engine quits without warning, or other electrical failures). The voltage regulator manages the voltage flowing through the car, especially to and from the battery. There are two carbon contacts on the regulator that control the magnetic field when the alternator is spinning and these contacts wear over time. A new set of contacts will be about 13mm in length. Anything less than 5mm and the voltage regulator should be replaced, regardless if that is the cause of your electrical problems or not. Most older mechanics will tell you to keep a spare regulator in your toolbox.

The carbon contacts can be replaced on their own but requires desoldering the old ones from the base and then soldering the new ones on. It may be easier to just replace the unit as a whole.

This is the OEM voltage regulator, made by Bosch or Hella. It's the one with the white base and fits most Bosch alternators from 1977-1995 (Valeo and other alternators look very different and have a black cover and base). This part number replaces the previous BMW part numbers - 12311271664, 12321279548, 12311722755, 12321711399 and Bosch part numbers 1197311021 and 1197311028.
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Bosch Air Temperature Sensor - E31, E32, E34, E36, E38
2X Entries For Our G87 M2 Sweepstakes! We Price Match - Give Us A Call or Chat!
Bosch - Corporate Logo
T#:555413
Part#: 13621725323
In Stock
$ 44.99

This product was last offered at the strikethrough price on
03-09-2026

$ 34.33 USD
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$ 34.33 USD
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Located on the intake manifold or intake box

OEM Bosch Remanufactured Alternator - 140 amp -- E32 735i/iL E34 530i...
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Bosch - Corporate Logo
T#:224664
Part#: AL148X
In Stock
$ 309.99

This product was last offered at the strikethrough price on
03-16-2026

$ 302.99 USD
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$ 302.99 USD
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If your car has died on the side of the road from a dead battery and you notice flickering or low powered head lights, it's likely your alternator failing. To be sure you are getting a high quality part with a long life-span, choose this OEM Bosch Alternator. OEM replacement from BMW part number 12311466088 and 12311735706

Bosch is one of the largest OEM producers of Genuine BMW and aftermarket parts in the world, providing parts for almost every major automotive manufacturer. Bosch has likely supplied many of the original electrical (and mechanical) parts for your BMW. Thanks to their quality, high durability, and reliability, you should expect a long service life from Bosch products.

As a leading source of high performance BMW parts and accessories since 1993, we at Turner Motorsport are honored to be the go-to supplier for tens of thousands of enthusiasts the world over. With over two decades of parts, service, and racing experience under our belt, we provide only quality performance and replacement parts.  All of our performance parts are those we would (and do!) install and run on our own cars, as well as replacement parts that are Genuine BMW or from OEM manufacturers. We only offer parts we know you can trust to perform!

A $65.00 refundable core charge is included with this alternator. Upon receipt of your rebuildable alternator core, you will be refunded the core charge. 

This Bosch Alternator fits the following BMWs:
1989-1993 E34 BMW 535i
1988-1992 E32 BMW 735i 735il

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Advanced Auto Fabrication - Corporate Logo
T#:7593105
Part#: 116177
Ships in 3 Business Days
$ 71.99 USD
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Since 2010, Advanced Auto Fabrication has been producing and developing both parts and full fledged race cars. Their knowledge base covers a wide range of vehicles both domestic and imported. In the specific case of BMW, the team at AAF has a particular affinity for building and designing components for BMW race cars. AAF's Oil Pressure Sensor Relocation Kit allows for an aftermarket low pressure switch as well as oil pressure sensor, or two 1/8' NPT pressure sensors to be installed. This can allow a gauge or light to be on the dash and still log oil pressure in a data logger. This kit also moves the oil pressure sensor away from the engine and onto the chassis (or any other spot) where is it much easier to access, or install larger size diameter sensors. Fits all M20 Engines. Features: 4AN Stainless Steel Braided Line Banjo Bolt and Fitting (installs onto block) 3 Way 1/8' NPT Tee Fitting, for hose from block and 2 sensors. Note: This kit does not come with sensors – the factory low pressure switch can NOT be used. An aftermarket 1/8″ NPT low pressure switch can be used with the factory wire.
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Hitachi Voltage Regulator - BMW E31 E32 E34 E36
For vehicles with compact alternator
Hitachi - Corporate Logo
T#:48850064
Part#: 12311747920
Ships in 6 Business Days
New Item
$ 37.99 USD
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$ 37.99 USD
Free Shipping on orders $49 and up
This voltage regulator is a crucial component that controls the alternator's output, preventing overcharging by adjusting the current to maintain a safe range of vehicle voltage, thereby protecting the battery and electrical system. Symptoms of failure include dim lights, battery warnings, or a dead battery, often requiring replacement, which can be internal or external to the alternator.
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OEM Bosch Fuel Pump Relay -- e30 e36 e46 e28 e34 e39 e24 e23 e32 e38 ...
2X Entries For Our G87 M2 Sweepstakes! We Price Match - Give Us A Call or Chat!
Bosch - Corporate Logo
T#:2857
Part#: 61311373585
In Stock
$ 11.99 USD
Free Shipping on orders $49 and up

If you have a faulty fuel pump relay, fuel will not be pumped to the engine and your engine may not start. Replace your relay with this high quality Bosch replacement to restore fuel pump operation.

Bosch is one of the largest OEM producers of Genuine BMW and aftermarket parts in the world, providing parts for almost every major automotive manufacturer. Bosch has likely supplied many of the original electrical (and mechanical) parts for your BMW. Thanks to their quality, high durability, and reliability, you should expect a long service life from Bosch products.

As a leading source of high performance BMW parts and accessories since 1993, we at Turner Motorsport are honored to be the go-to supplier for tens of thousands of enthusiasts the world over. With over two decades of parts, service, and racing experience under our belt, we provide only quality performance and replacement parts.  All of our performance parts are those we would (and do!) install and run on our own cars, as well as replacement parts that are Genuine BMW or from OEM manufacturers. We only offer parts we know you can trust to perform!

This 4 prong relay fits many BMW's and fulfulls a variety of functions. Please check your relay pins configuration to ensure the proper fitment. Fits BMW 2002, e30 e36 e46 e28 e34 e39 e24 e23 e32 e38 e31 z3


This item fits the following BMWs:
1970-1976 2002 BMW 1600 2002 2002tii
1984-1991 E30 BMW 318i 318is 318ic 325e 325es 325i 325ic 325is 325ix M3
1992-1998 E36 BMW 318i 318is 318ti 318ic 323is 323ic 325i 325is 325ic 328i 328is 328ic M3
1999-2005 E46 BMW 323i 323ci 325i 325ci 325xi 328i 328ci 330i 330ci 330xi M3
1982-1988 E28 BMW 524td 528e 533i 535i 535is M5
1989-1995 E34 BMW 525i 530i 535i 540i M5
1997-2003 E39 BMW 525i 528i 530i 540i M5
1982-1989 E24 BMW 633csi 635csi M6
1981-1987 E23 BMW 733i 735i
1988-1994 E32 BMW 735i 735il 740i 740il 750il
1995-2001 E38 BMW 740i 740il 750il
1990-1999 E31 BMW 840i 840ci 850i 850ci 850csi
1997-2002 Z3 BMW Z3 1.9 Z3 2.3 Z3 2.5i Z3 2.8 Z3 3.0i M coupe M Roadster

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15A Fuse - Priced Each
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Bosch - Corporate Logo
T#:375327
Part#: 61131372626
In Stock at Vendor
$ 2.03 USD
Free Shipping on orders $49 and up

Bosch Alternator - 1993 E34 525i & 525i Touring (1993 only)
2X Entries For Our G87 M2 Sweepstakes! We Price Match - Give Us A Call or Chat!
Bosch - Corporate Logo
T#:1675
Part#: AL0741X
Ships on Aug 14, 2026
$ 389.99 USD
Free Shipping on orders $49 and up

115 amp Bosch alternator for 1993 525i & 525i Touring (the E34 chassis). Bosch is an original equipment supplier to BMW, and is the finest and most recognized German brand of alternator available. Buy only the best alternator for your BMW -- buy a Bosch alternator.

Bosch is one of the largest OEM producers of Genuine BMW and aftermarket parts in the world, providing parts for almost every major automotive manufacturer. Bosch has likely supplied many of the original electrical (and mechanical) parts for your BMW. Thanks to their exacting assembly process and high level of durability you can expect a long service life from all Bosch products.

A refundable core charge must be applied to this alternator. Upon receipt of your rebuildable alternator core, you will be refunded the core charge.

This Bosch Alternator fits the following BMWs:
1993-1993 E34 5 Series 525i & 525i Touring (1993 model only)

Includes $123.00 core charge to be refunded on return of your rebuildable core.

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Bosch Alternator - E34 525i 1989-1990 (M20 Engine) - 140 amp ...
2X Entries For Our G87 M2 Sweepstakes! We Price Match - Give Us A Call or Chat!
Bosch - Corporate Logo
T#:1988
Part#: AL0154X
Ships on Aug 14, 2026
$ 409.99 USD
Free Shipping on orders $49 and up
A replacement 140 amp Bosch alternator for the 1989-1990 525i. 

Bosch is one of the largest OEM producers of Genuine BMW and aftermarket parts in the world, providing parts for almost every major automotive manufacturer. Bosch has likely supplied many of the original electrical (and mechanical) parts for your BMW. Thanks to their exacting assembly process and high level of durability you can expect a long service life from all Bosch products.

A refundable core charge must be applied to this alternator. Upon receipt of your rebuildable alternator core, you will be refunded the core charge. 

This Bosch alternator fits the following BMWs:
1989-1990  E34 5 Series  525i & 525i wagon
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Hitachi - Corporate Logo
T#:48850070
Part#: 12321739435
Back Ordered
New Item
$ 60.99 USD
Free Shipping on orders $49 and up
$ 60.99 USD
Free Shipping on orders $49 and up
Alternator voltage regulators are a crucial component that controls the alternator's output, preventing overcharging by adjusting the current to keep vehicle voltage within a safe range, protecting the battery and electrical system. Symptoms of failure include dim lights, battery warnings, or a dead battery, often requiring replacement, which can be internal or external to the alternator
Show More Show Less