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BMW Electrical Sensors, Switches, & Relays

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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Turner Motorsport - Corporate Logo
T#:55497484
Part#: 060119LA02KT
Ships in 3 Business Days
New Item
$ 73.99

This product was last offered at the strikethrough price on
09-29-2026

$ 71.99 USD
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$ 71.99 USD
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The Turner Motorsport M57 Clutched Alternator Pulley Conversion Kit for BMW E70 X5 35d M57 engines converts rigid factory pulleys to an overrunning clutched setup. Rigid stock pulleys transmit crankshaft micro-accelerations, driving belt chatter and harmonic balancer failure. Combining an OE N52 clutched pulley with a zinc-coated alloy steel spacer isolates rotational inertia to protect accessory drive components.
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Turner Motorsport - Corporate Logo
T#:55497480
Part#: 060119LA01KT
Ships in 3 Business Days
New Item
$ 73.99

This product was last offered at the strikethrough price on
09-29-2026

$ 71.99 USD
Free Shipping
$ 71.99 USD
Free Shipping

If you own an M57-equipped BMW, you already know this twin-turbo diesel powerplant is an absolute torque monster. What you might also know is that all that low-end grunt and high-compression diesel vibration wreaks absolute havoc on your accessory drive system.

From the factory, both the E90 335d and E70 X5 35d utilize a rigid alternator pulley. With each cylinder's fire, the crankshaft experiences a violent micro-acceleration. Because the alternator has a heavy internal rotor spinning at high speeds, it wants to keep spinning at a constant rate. When the engine suddenly slows down (even minutely between firing cycles), the alternator fights the belt. This constant tug-of-war results in extreme stress on your engine's belt-driven components. At best, it’s an annoying, unrefined chirp at idle; at worst, it’s a ticking time bomb for your expensive harmonic balancer.

To solve this issue, many enthusiasts choose to run a clutched alternator pulley (also called an overrunning alternator pulley). A clutched pulley allows the alternator to "freewheel" or coast when the engine slows down, completely isolating its rotational inertia from the belt drive to prevent component wear. While the N52's clutched pulley (12317560483) is a straight bolt-on, the offset is incorrect for the E90 335d's accessory drive. Thankfully, our engineers designed this zinc-coated spacer to provide the precise amount of spacing needed to perfectly align the new pulley with existing belt drive components.

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Turner Motorsport - Corporate Logo
T#:55497479
Part#: 060119LA02
In Stock
New Item
$ 9.99 USD
Free Shipping
$ 9.99 USD
Free Shipping

If you own an M57-equipped BMW, you already know this twin-turbo diesel powerplant is an absolute torque monster. What you might also know is that all that low-end grunt and high-compression diesel vibration wreaks absolute havoc on your accessory drive system.

From the factory, both the E90 335d and E70 X5 35d utilize a rigid alternator pulley. With each cylinder's fire, the crankshaft experiences a violent micro-acceleration. Because the alternator has a heavy internal rotor spinning at high speeds, it wants to keep spinning at a constant rate. When the engine suddenly slows down (even minutely between firing cycles), the alternator fights the belt. This constant tug-of-war results in extreme stress on your engine's belt-driven components. At best, it’s an annoying, unrefined chirp at idle; at worst, it’s a ticking time bomb for your expensive harmonic balancer.

To solve this issue, many enthusiasts choose to run a clutched alternator pulley (also called an overrunning alternator pulley). A clutched pulley allows the alternator to "freewheel" or coast when the engine slows down, completely isolating its rotational inertia from the belt drive to prevent component wear. While the N52's clutched pulley (12317560483) is a straight bolt-on, the offset is incorrect for the E70 X5 35d's accessory drive. Thankfully, our engineers designed this zinc-coated spacer to provide the precise amount of spacing needed to perfectly align the new pulley with existing belt drive components.

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Turner Motorsport - Corporate Logo
T#:55497466
Part#: 060119LA01
In Stock
New Item
$ 9.99 USD
Free Shipping
$ 9.99 USD
Free Shipping

If you own an M57-equipped BMW, you already know this twin-turbo diesel powerplant is an absolute torque monster. What you might also know is that all that low-end grunt and high-compression diesel vibration wreaks absolute havoc on your accessory drive system.

From the factory, both the E90 335d and E70 X5 35d utilize a rigid alternator pulley. With each cylinder's fire, the crankshaft experiences a violent micro-acceleration. Because the alternator has a heavy internal rotor spinning at high speeds, it wants to keep spinning at a constant rate. When the engine suddenly slows down (even minutely between firing cycles), the alternator fights the belt. This constant tug-of-war results in extreme stress on your engine's belt-driven components. At best, it’s an annoying, unrefined chirp at idle; at worst, it’s a ticking time bomb for your expensive harmonic balancer.

To solve this issue, many enthusiasts choose to run a clutched alternator pulley (also called an overrunning alternator pulley). A clutched pulley allows the alternator to "freewheel" or coast when the engine slows down, completely isolating its rotational inertia from the belt drive to prevent component wear. While the N52's clutched pulley (12317560483) is a straight bolt-on, the offset is incorrect for the E90 335d's accessory drive. Thankfully, our engineers designed this zinc-coated spacer to provide the precise amount of spacing needed to perfectly align the new pulley with existing belt drive components.

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Bosch Starter Motor With Hardware
10X Entries Into Our F80 M3 Sweepstakes
Packaged by Turner - Corporate Logo
T#:56110332
Part#: SR0492NKT4
In Stock
New Item
$ 273.99

This product was last offered at the strikethrough price on
08-14-2026

$ 261.99 USD
Free Shipping on orders $49 and up
$ 261.99 USD
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At the core is a brand-new Bosch Starter Motor, engineered to withstand extreme operating conditions while delivering immediate cranking speed. This kit includes also the required Genuine BMW Aluminum Mounting Screw Set.
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Bosch - Corporate Logo
T#:54388475
Part#: 13627636937
In Stock
New Item
$ 29.99 USD
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Keep your ignition timing razor-sharp and your engine safe from destructive detonation. This replacement Knock Sensor acts as your engine's first line of defense, constantly listening for pre-ignition "pinging" or knocking.
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SEG Automotive - Corporate Logo
T#:54851991
Part#: 12317560985
Ships in 1 Business Day
New Item
$ 1,049.99

This product was last offered at the strikethrough price on
07-16-2026

$ 961.99 USD
Free Shipping on orders $49 and up
$ 961.99 USD
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SEG Automotive - Corporate Logo
T#:54851993
Part#: 12317613445
Ships in 1 Business Day
New Item
$ 564.99

This product was last offered at the strikethrough price on
07-16-2026

$ 521.99 USD
Free Shipping on orders $49 and up
$ 521.99 USD
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SEG Automotive - Corporate Logo
T#:55857741
Part#: 12417610344
Ships in 1 Business Day
New Item
$ 368.99

This product was last offered at the strikethrough price on
07-16-2026

$ 337.99 USD
Free Shipping on orders $49 and up
$ 337.99 USD
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SEG Automotive - Corporate Logo
T#:54851980
Part#: 12317519618
Ships in 1 Business Day
New Item
$ 503.99

This product was last offered at the strikethrough price on
07-16-2026

$ 462.99 USD
Free Shipping on orders $49 and up
$ 462.99 USD
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SEG Automotive - Corporate Logo
T#:54851997
Part#: 12411489995
Ships in 1 Business Day
New Item
$ 432.99

This product was last offered at the strikethrough price on
07-16-2026

$ 406.99 USD
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$ 406.99 USD
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Vargas Turbo Technologies - Corporate Logo
T#:52129729
Part#: VTT56BSENSKIT64
Ships in 10 Business Days
New Item
$ 209.99 USD
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$ 209.99 USD
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The VTT 6-Bar MAP sensor kit provides the necessary overhead to monitor boost levels with a linear voltage scale that makes software calibration straightforward.


Vargas Turbo Technologies - Corporate Logo
T#:51672717
Part#: VTT-MAP-HARNESS
Ships in 10 Business Days
New Item
$ 59.99 USD
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$ 59.99 USD
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As part of the VTT-FAB fabrication line, this extension harness is designed for builders and tuners who need flexibility.
Vargas Coolant Level Extension Harness - BMW B48/B58/S58
2X Entries Into Our F80 M3 Sweepstakes
Vargas Turbo Technologies - Corporate Logo
T#:51813310
Part#: VTT-FAB-HC
Ships in 10 Business Days
New Item
$ 49.99 USD
Free Shipping
$ 49.99 USD
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Simplify your next fabrication project with the VTT-FAB series Coolant Extension Harness.
SEG Automotive - Corporate Logo
T#:54851988
Part#: 12317550319
Ships in 1 Business Day
New Item
$ 473.99

This product was last offered at the strikethrough price on
07-16-2026

$ 436.99 USD
Free Shipping on orders $49 and up
$ 436.99 USD
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SEG Automotive - Corporate Logo
T#:54851984
Part#: 12317541694
Ships in 1 Business Day
New Item
$ 521.99

This product was last offered at the strikethrough price on
07-16-2026

$ 474.99 USD
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$ 474.99 USD
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Vargas USB To Serial For HPFP Controller - BMW N54
2X Entries Into Our F80 M3 Sweepstakes
Vargas Turbo Technologies - Corporate Logo
T#:51778112
Part#: N54-USB-SERIAL-H
Ships in 10 Business Days
New Item
$ 37.99 USD
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$ 37.99 USD
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Take full control of your N54’s fueling system with the Vargas Turbo Technologies USB to Serial adapter.

Genuine BMW - Corporate Logo
T#:55281756
Part#: 61138TRKT
Ships in 1-2 days
New Item
$ 42.36 USD
Free Shipping on orders $49 and up
This terminal repair kit is the ideal companion for refreshing damaged wiring pins and keeping your chassis' electrical system functioning flawlessly.
Genuine BMW - Corporate Logo
T#:55785659
Part#: 61278882634
Ships in 1-2 days
New Item
3% off MSRP $ 1,572.99

MSRP stands for Manufacturer's Suggested Retail Price. This is the suggested retail price provided by the manufacturer, supplier or seller.

$ 1,532.99 USD
Free Shipping on orders $49 and up
3% off MSRP
$ 1,572.99

MSRP stands for Manufacturer's Suggested Retail Price. This is the suggested retail price provided by the manufacturer, supplier or seller.

$ 1,532.99 USD
Free Shipping on orders $49 and up
When this critical high-voltage module succumbs to internal hardware failure or water intrusion, your PHEV BMW will instantly lock out its charging capabilities and disable all electric driving modes to protect the vehicle's complex electrical grid. Don't let a failed module keep your hybrid system sidelined. This Genuine BMW replacement unit is the exact factory-spec computer required to replace your corrupted original, fully restoring accurate electric range reporting, optimal cell balancing, and crucial factory safety parameters to your high-voltage accumulator pack.
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Genuine BMW - Corporate Logo
T#:55281746
Part#: 125275WRKT
Ships in 6 Business Days
New Item
$ 37.40 USD
Free Shipping on orders $49 and up
This Genuine BMW wiring repair kit is the ideal solution to refresh worn-out terminal connections in your Ultimate Driving Machine.

Genuine BMW - Corporate Logo
T#:56869523
Part#: 12145B94D28
Ships in 6 Business Days
New Item
3% off MSRP $ 3,430.99

MSRP stands for Manufacturer's Suggested Retail Price. This is the suggested retail price provided by the manufacturer, supplier or seller.

$ 3,321.99 USD
Free Shipping on orders $49 and up
3% off MSRP
$ 3,430.99

MSRP stands for Manufacturer's Suggested Retail Price. This is the suggested retail price provided by the manufacturer, supplier or seller.

$ 3,321.99 USD
Free Shipping on orders $49 and up
SEG Automotive - Corporate Logo
T#:58965210
Part#: 0124.515.052
Ships on Nov 3, 2026
New Item
$ 485.99 USD
Free Shipping on orders $49 and up
A strong charging system keeps everything from your ignition to your stereo working at its best, and a failing alternator can undermine all of it.
SEG Automotive - Corporate Logo
T#:58965213
Part#: 0124.525.523
Ships on Nov 3, 2026
New Item
$ 495.99 USD
Free Shipping on orders $49 and up
Your BMW's charging system powers everything from ignition to infotainment, so a weak alternator affects the whole car.


SEG Automotive - Corporate Logo
T#:59001789
Part#: 12417570487
Ships on Nov 3, 2026
New Item
$ 325.99 USD
$ 325.99 USD
This SEG Automotive unit is built as a direct replacement for the factory 0.9 kW starter on the R50 Hatch and R52 Convertible.
SEG Automotive - Corporate Logo
T#:58965212
Part#: 0124.525.561
Ships on Nov 3, 2026
New Item
$ 487.99 USD
Free Shipping on orders $49 and up
SEG Automotive, the company behind Bosch's starter motor and generator business, builds this brand-new 150-amp alternator with a freewheel pulley that smooths out belt loads for a quieter, longer-lasting accessory drive.
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SEG Automotive - Corporate Logo
T#:58965209
Part#: 0001.148.508
Ships on Nov 3, 2026
New Item
$ 274.99 USD
Free Shipping on orders $49 and up
A healthy starter is what gets your BMW from parked to pulling away without a second thought.

SEG Automotive - Corporate Logo
T#:59001785
Part#: 12311711204
Ships on Nov 3, 2026
New Item
$ 726.99 USD
$ 726.99 USD
The E24 M635CSi is one of BMW's great grand tourers, and keeping one healthy means a charging system you can count on.

SEG Automotive - Corporate Logo
T#:58965208
Part#: 0001.170.202
Ships on Nov 3, 2026
New Item
$ 216.99 USD
Free Shipping on orders $49 and up
The smart choice for F-chassis owners who want their car starting on the first try, every time.
SEG Automotive - Corporate Logo
T#:59001784
Part#: 12417616698
Ships on Nov 3, 2026
New Item
$ 275.99 USD
$ 275.99 USD
On a MINI built for quick, spirited driving, there is no reason to put up with slow or hesitant cranking.

SEG Automotive - Corporate Logo
T#:59001787
Part#: 12418589891
Ships on Nov 3, 2026
New Item
$ 276.99 USD
$ 276.99 USD
Modern G-chassis BMWs deliver serious performance, and none of it matters if the engine won't start.
Bosch - Corporate Logo
T#:57267766
Part#: 12317605478
Special Order: No Guaranteed ETA
New Item
$ 499.99 USD
Free Shipping on orders $49 and up
Maintain peak battery performance and protect your vehicle's complex electrical architecture with a motorsport-tested, factory-grade charging replacement.

Bosch - Corporate Logo
T#:57267768
Part#: 12317616126
Special Order: No Guaranteed ETA
New Item
$ 571.99 USD
Free Shipping on orders $49 and up
Keep your BMW's vital electronics powered and your engine running at peak efficiency with a premium remanufactured alternator from Bosch.

Bosch - Corporate Logo
T#:57304035
Part#: SR3295N
Special Order: No Guaranteed ETA
New Item
$ 441.99 USD
Free Shipping on orders $49 and up
This new starter delivers crisp power and rapid engine speed recovery, avoiding the typical voltage drop issues associated with worn original units.
Bosch - Corporate Logo
T#:57231530
Part#: 12411427080
Special Order: No Guaranteed ETA
New Item
$ 78.99 USD
Free Shipping on orders $49 and up
When you are at the track or gearing up for a weekend backroad drive, the last thing you need is a sluggish starter holding your BMW back.
Bosch - Corporate Logo
T#:57267806
Part#: 12418625995
Special Order: No Guaranteed ETA
New Item
$ 463.99 USD
Free Shipping on orders $49 and up
Bosch starter units deliver the high-torque cranking performance required to reliably start modern high-compression BMW engines under all thermal conditions.


Bosch - Corporate Logo
T#:57267807
Part#: 12418621839
Special Order: No Guaranteed ETA
New Item
$ 342.99 USD
Free Shipping on orders $49 and up
Bosch - Corporate Logo
T#:57304037
Part#: 12417843530
Special Order: No Guaranteed ETA
New Item
$ 412.99 USD
Free Shipping on orders $49 and up
Ensure your high-performance engine cranks reliably every time with an OE-quality starter motor from Bosch.
Bosch - Corporate Logo
T#:57231540
Part#: 12311466084
Special Order: No Guaranteed ETA
New Item
$ 286.99 USD
Free Shipping on orders $49 and up
Ensure your BMW or European vehicle maintains uninterrupted power under demanding driving conditions with this premium remanufactured alternator by Bosch.

Bosch - Corporate Logo
T#:57267767
Part#: 12317561004
Special Order: No Guaranteed ETA
New Item
$ 695.99 USD
Free Shipping on orders $49 and up
This Bosch remanufactured alternator delivers the rock-solid current required to keep your ignition, fuel management, and chassis electronics operating at peak efficiency under demanding conditions.

Bosch - Corporate Logo
T#:57267763
Part#: AL0757X
Special Order: No Guaranteed ETA
New Item
$ 430.99 USD
Free Shipping on orders $49 and up
This high-output Bosch remanufactured alternator ensures your ignition system and performance electronics receive clean, steady amperage under high-demand driving conditions.
Bosch - Corporate Logo
T#:57376671
Part#: SR71XKT
Back Ordered
New Item
$ 342.99

This product was last offered at the strikethrough price on
08-23-2026

$ 212.99 USD
Free Shipping on orders $49 and up
$ 212.99 USD
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The Bosch SR71X Remanufactured Starter delivers the precise, high torque cranking performance needed to keep your vehicle starting cleanly on the street or at the track

Bosch - Corporate Logo
T#:57376634
Part#: AL0839XKT
Back Ordered
New Item
$ 476.86

This product was last offered at the strikethrough price on
08-23-2026

$ 422.86 USD
Free Shipping on orders $49 and up
$ 422.86 USD
Free Shipping on orders $49 and up
Protect your BMW's electrical performance on the road and track with the Bosch AL0839X remanufactured alternator. Designed to handle high demand electrical loads under spirited driving conditions