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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
In Stock
New Item
$ 73.99 USD
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$ 73.99 USD
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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 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#:55497480
Part#: 060119LA01KT
In Stock
New Item
$ 73.99 USD
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$ 73.99 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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ECS - Corporate Logo
T#:49996974
Part#: 059235LA01
In Stock
New Item
Sale - Save 20% $ 29.99

This product was last offered at the strikethrough price on
06-14-2026

$ 23.99 USD
Free Shipping
Sale - Save 20%
$ 29.99

This product was last offered at the strikethrough price on
06-14-2026

$ 23.99 USD
Free Shipping

If you're experiencing hard starting, flaky charging, or other electrical issues, your engine ground strap may be the culprit. On older BMWs, the engine ground strap is a thin, non-insulated cable that spans from the engine mount arm to the frame horn. Despite the seemingly simple nature of this part, on older cars, it is known to cause massive headaches. Due to its non-insulated design, years of exposure to water, dirt, and road salt will cause the wire to corrode, ultimately leading to complete failure. A break in this cable will cause an open circuit, resulting in issues with the vehicle's electrical system and potentially leading to a no-start condition.

To solve this issue, ECS has engineered an exact-fit, upgraded ground strap for your BMW! Unlike its OEM counterpart, this design features insulated, large-gauge copper wire for dependable conductivity and long-lasting durability. Additionally, factory-style lugs are zinc-coated, crimped, and soldered, ensuring protection against corrosion and oxidation.

Whether you're replacing a visibly corroded strap or proactively preventing failure, this solution from ECS is sure to provide lasting performance and protection.

FEATURES

Direct-fit replacement and upgrade for E30 (318i/is), E36, E39, E46, and others Solves intermittent grounding issues caused by aging OEM straps Clean, stealthy design that fits seamlessly in factory engine bays Factory length and lug orientation for drop-in fitment 2 AWG tinned copper cable for excellent conductivity and corrosion resistance Zinc-coated lugs, crimped and soldered to resist moisture and oxidation Black UL1015-grade insulation withstands oil, heat, and abrasion Discreet ECS label for a clean, OEM+ look Replaces OEM part numbers 12421737755 and 12421714262.

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ECS - Corporate Logo
T#:49996976
Part#: 059261LA01
Ships in 4 Business Days
New Item
Sale - Save 25% $ 29.99

This product was last offered at the strikethrough price on
06-14-2026

$ 22.49 USD
Free Shipping
Sale - Save 25%
$ 29.99

This product was last offered at the strikethrough price on
06-14-2026

$ 22.49 USD
Free Shipping

If you're experiencing hard starting, flaky charging, or other electrical issues, your engine ground strap may be the culprit. On E70/E71 BMWs, the engine ground strap is a thin, non-insulated cable that spans from the left engine mount arm to the frame horn. Despite the seemingly simple nature of this part, on older cars, it is known to cause massive headaches. Due to its non-insulated design, years of exposure to water, dirt, and road salt will cause the wire to corrode, ultimately leading to complete failure. A break in this cable will cause an open circuit, resulting in issues with the vehicle's electrical system and potentially leading to a no-start condition.

To solve this issue, ECS has engineered an exact-fit, upgraded ground strap for your BMW X5/X6! Unlike its OEM counterpart, this design features insulated, large-gauge copper wire for dependable conductivity and long-lasting durability. Additionally, factory-style lugs are zinc-coated, crimped, and soldered, ensuring protection against corrosion and oxidation.

Whether you're replacing a visibly corroded strap or proactively preventing failure, this solution from ECS is sure to provide lasting performance and protection.

FEATURES

Direct-fit replacement and upgrade for E70 X5 and E71 X6 applications Solves intermittent grounding issues caused by aging OEM straps Clean, stealthy design that fits seamlessly in factory engine bays Factory length and lug orientation for drop-in fitment 2 AWG tinned copper cable for excellent conductivity and corrosion resistance Zinc-coated lugs, crimped and soldered to resist moisture and oxidation Black UL1015-grade insulation withstands oil, heat, and abrasion Discreet ECS label for a clean, OEM+ look Replaces OEM part number 12427557027.

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Hitachi - Corporate Logo
T#:48850064
Part#: 12311747920
Ships in 6 Business Days
New Item
$ 37.99 USD
Free Shipping on orders $49 and up
$ 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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MHD Tuning - Corporate Logo
T#:54852023
Part#: MHD-UNLOCKER
Ships on Aug 11, 2026
New Item
$ 373.99 USD
$ 373.99 USD
MHD Unlocker with a plug and play harness/connections - Simple and easy unlock at home in a few minutes!

Packaged by Turner - Corporate Logo
T#:56110332
Part#: SR0492NKT4
In Stock
New Item
$ 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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Hitachi - Corporate Logo
T#:48850059
Part#: 13628697982
Ships in 6 Business Days
New Item
$ 48.99 USD
$ 48.99 USD
The camshaft position sensor communicates the position of the camshaft to the computer. This helps the computer to calculate proper spark and fuel control. If you're struggling with CELs, hard starts or no starts, stalling, and/or a rough idle, you may need to replace the cam position sensor.
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Hitachi - Corporate Logo
T#:48815454
Part#: 13627525014
Ships in 6 Business Days
New Item
$ 40.00 USD
Free Shipping on orders $49 and up
The camshaft position sensor communicates the position of the camshaft to the computer. This helps the computer to calculate proper spark and fuel control. If you're struggling with CELs, hard starts or no starts, stalling, and/or a rough idle, you may need to replace the cam position sensor.
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Hitachi - Corporate Logo
T#:48850074
Part#: 13627582842
Ships in 6 Business Days
New Item
$ 184.99 USD
Free Shipping on orders $49 and up
Engine cranks but doesn't start? This sensor is often the issue.
Hitachi - Corporate Logo
T#:48850055
Part#: 12147518628
Ships in 2 Business Days
New Item
$ 71.99 USD
Free Shipping on orders $49 and up
The camshaft position sensor is essential for assisting the engine DME by monitoring the camshaft's position. The data from this sensor is key to optimizing ignition timing and ensuring smooth engine performance. Often referred to as the CMP sensor, this component is crucial for the overall functionality of the powertrain. A failing camshaft position sensor can cause a range of issues, including engine stumbling, hesitation during acceleration, power loss, and even starting difficulties or complete failure to start.
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Hitachi - Corporate Logo
T#:48850072
Part#: 12147539165
In Stock at Vendor
New Item
$ 41.99 USD
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$ 41.99 USD
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A bad cam sensor can cause a variety of problems from hard starting to stalling at low speeds. Cam sensor replacement has been known to cure many drivabilty issues. Uses O-ring # 12 141 748 398 (not included)
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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.

Hitachi - Corporate Logo
T#:48815471
Part#: 13627525015
Ships in 6 Business Days
New Item
$ 66.99 USD
Free Shipping on orders $49 and up
The crankshaft position sensor transmits the crankshaft's position to the computer. This helps the computer to calculate proper spark and fuel control. If you're struggling with CELs, hard starts or no starts, stalling, and/or a rough idle, you may need to replace the crank position sensor.
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Hitachi - Corporate Logo
T#:48850081
Part#: 13627806782
Ships in 6 Business Days
New Item
$ 81.99 USD
Free Shipping on orders $49 and up
Tells the computer whether the timing is correct in the engine.

Vargas Turbo Technologies - Corporate Logo
T#:51813310
Part#: VTT-FAB-HC
Ships in 10 Business Days
New Item
$ 49.99 USD
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$ 49.99 USD
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Simplify your next fabrication project with the VTT-FAB series Coolant Extension Harness.
Hitachi - Corporate Logo
T#:48815477
Part#: 12317550469
Ships in 6 Business Days
New Item
$ 79.99 USD
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Supplies power to your car's electronics and recharges the battery.

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 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#:55785659
Part#: 61278882634
Ships in 2 Business 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#:49508960
Part#: 61278884872
Ships in 2 Business Days
New Item
5% off MSRP $ 259.99

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

$ 247.99 USD
Free Shipping on orders $49 and up
5% off MSRP
$ 259.99

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

$ 247.99 USD
Free Shipping on orders $49 and up
Genuine BMW communication wiring harness


Genuine BMW - Corporate Logo
T#:55281756
Part#: 61138TRKT
Ships in 2 Business Days
New Item
$ 42.36 USD
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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#:49543753
Part#: 12145B32771
Ships in 4 Business Days
New Item
3% off MSRP $ 2,409.99

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

$ 2,333.99 USD
Free Shipping on orders $49 and up
3% off MSRP
$ 2,409.99

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

$ 2,333.99 USD
Free Shipping on orders $49 and up
Replaces faulty or broken cotrol unit
Genuine BMW - Corporate Logo
T#:50311456
Part#: 12425B586B0
Ships in 8 Business Days
New Item
3% off MSRP $ 60.99

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

$ 58.99 USD
Free Shipping on orders $49 and up
3% off MSRP
$ 60.99

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

$ 58.99 USD
Free Shipping on orders $49 and up
Your vehicle’s ground strap plays a vital role in maintaining a healthy electrical system. Exposure to heat, corrosion, and constant vibration can degrade the strap over time, resulting in weak or inconsistent electrical connections. When the ground strap begins to fail, symptoms can include hard starting, flickering or dim lights, warning messages, erratic sensor behavior, or complete no-start situations. Replacing a worn ground strap restores proper current flow, protects sensitive electronics, and keeps your engine and electrical systems operating reliably.
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Genuine BMW - Corporate Logo
T#:55281746
Part#: 125275WRKT
Ships in 7 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.

Hitachi - Corporate Logo
T#:48815470
Part#: 12141709616
Back Ordered
New Item
$ 32.99 USD
Free Shipping on orders $49 and up
NOTE: Does not include o-ring seal - see BMW # 12141748398 This is the crankshaft position sensor. It provides information for the ECU. A faulty sensor can cause issues with timing adjustment and limit performance and vehicle operation. Replace your sensor with a high-quality Hitachi sensor to restore peak performance.
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Hitachi - Corporate Logo
T#:48815475
Part#: 13627595860
Back Ordered
New Item
$ 68.99 USD
Free Shipping on orders $49 and up
This is the crankshaft position sensor. It provides information for the ECU. A faulty sensor can cause issues with timing adjustment and limit performance and vehicle operation. Replace your sensor with a high-quality Hitachi sensor to restore peak performance.
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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