BMW Electrical Sensors, Switches, & Relays for BMW 3 Series E46 (1999-2005)

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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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ECS Heavy Duty Ground Cable Upgrade (12421737755) - E30, E36, E39, E4...
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ECS - Corporate Logo
T#:49996974
Part#: 059235LA01
In Stock
Sale - Save 25% $ 29.99

This product was last offered at the strikethrough price on
11-07-2026

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

This product was last offered at the strikethrough price on
11-07-2026

$ 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 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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New Alternator - 120A
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Bavarian Autosport - Corporate Logo
T#:25042543
Part#: 12317501690
In Stock
Sale - Save 20% $ 211.99

This product was last offered at the strikethrough price on
11-07-2026

$ 169.59 USD
Free Shipping on orders $49 and up
Sale - Save 20%
$ 211.99

This product was last offered at the strikethrough price on
11-07-2026

$ 169.59 USD
Free Shipping on orders $49 and up
Alternator - 120amp
10X Entries Into Our F80 M3 Sweepstakes 10X Entries For Our Spin To Win Sweepstakes!
Bavarian Autosport - Corporate Logo
T#:25042542
Part#: 12317831436
In Stock
Sale - Save 25% $ 222.99

This product was last offered at the strikethrough price on
11-07-2026

$ 167.24 USD
Free Shipping on orders $49 and up
Sale - Save 25%
$ 222.99

This product was last offered at the strikethrough price on
11-07-2026

$ 167.24 USD
Free Shipping on orders $49 and up

Advanced Auto Fabrication - Corporate Logo
T#:7608844
Part#: 11648
In Stock at Vendor
$ 28.99 USD
Free Shipping on orders $49 and up
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. The AAF E46 Jump Post Relocation Bracket makes it easy to adjust camber/caster on your race car by getting the factory jump post out of the way! In race car applications, the desired camber and caster settings can cause the strut tops and shock adjusters to interfere with the factory jump post. This kit takes just a few minutes to install and makes using strut braces and adjusting camber plates just that much safer and faster.
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PIAA - Corporate Logo
T#:31158805
Part#: 85115
Ships on Dec 7, 2026
$ 77.99 USD
Free Shipping on orders $49 and up
Superior Bass Sports Horn Kit 330Hz + 400Hz 112Db

The Superior Bass Sports Horn Kit 330Hz + 400Hz 112Db is designed to make sure your presence is known with powerful, attention-grabbing sound. These high-performance sports horns feature:

  • Impressive Loudness: Delivers a powerful 112 decibels, ensuring you’re heard in any situation.
  • Dual Frequency: Includes 330Hz and 400Hz horns for a dynamic and distinct sound.
  • Lightweight & Durable: Constructed for easy installation with weather-resistant covers, built to withstand the elements.
  • Easy Installation: Quick and straightforward to install, enhancing vehicle safety with minimal effort.

The kit is a must-have for anyone looking to enhance their vehicle’s horn performance and visibility on the road.

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Precision Raceworks - Corporate Logo
T#:35559424
Part#: 201-0411
In Stock
$ 34.99 USD
Free Shipping on orders $49 and up
n Ethanol Sensor Breakout Harness provides a clean wiring solution by splitting the signal from your ethanol content sensor between two analyzers, such as an ECU/controller and a gauge or Bluetooth display, without modifying your existing harness.his setup enables real-time ethanol level monitoring and facilitates comprehensive DME/ECU adjustments for enhanced automotive performance.citeturn0search0
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Race German - Corporate Logo
T#:2602224
Part#: E46FUSEKIT
Ships in 1 Business Day
$ 47.99 USD
Free Shipping on orders $49 and up
Complete set of fuses from OE BMW supplier for direct replacement of blown or mismatched fuses. Kit includes A complete set of new OEM fuses Extra fuses Fuse puller

LK-2M 2 Pin Connector Package
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ECS - Corporate Logo
T#:40072446
Part#: LK2M
In Stock
Sale - Save 34% $ 6.99

This product was last offered at the strikethrough price on
11-07-2026

$ 4.61 USD
Free Shipping on orders $49 and up
Sale - Save 34%
$ 6.99

This product was last offered at the strikethrough price on
11-07-2026

$ 4.61 USD
Free Shipping on orders $49 and up

Includes connector housing with terminals and seals. Commonly used for the engine oil pressure switch.

ECS Tuning replacement harness connectors include all necessary pins and wire seals for a complete harness repair. Whether you have a broken harness connector or need a complete wiring repair, we have the components you need.

Each connector includes an additional terminal in case one becomes lost or damaged during installation.

Suggested tools:

Suggested crimping pliers: T#387193
Wire De-pin tools:
12pc De-Pin Tool Set - T#386379
23pc De-Pin Tool Set - T#641943

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3 Pin Connector
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ECS - Corporate Logo
T#:33412931
Part#: 12527519996
In Stock
Sale - Save 40% $ 10.99

This product was last offered at the strikethrough price on
11-07-2026

$ 6.59 USD
Free Shipping on orders $49 and up
Sale - Save 40%
$ 10.99

This product was last offered at the strikethrough price on
11-07-2026

$ 6.59 USD
Free Shipping on orders $49 and up

Includes connector housing with terminals and seals. Commonly used for the pencil-style ignition coil connector.

ECS Tuning replacement harness connectors include all necessary pins and wire seals for a complete harness repair. Whether you have a broken harness connector or need a complete wiring repair, we have the components you need.

Each connector includes an additional terminal in case one becomes lost or damaged during installation.

*OEM cross reference PN# 12527519996 - Commonly used for the pencil-style ignition coil connector.

Please reference the original part number from the existing connector to confirm fitment, before ordering.

Suggested tools:

Suggested crimping pliers: T#387193
Wire De-pin tools:
12pc De-Pin Tool Set - T#386379
23pc De-Pin Tool Set - T#641943

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3 Pin Connector
10X Entries Into Our F80 M3 Sweepstakes 10X Entries For Our Spin To Win Sweepstakes!
ECS - Corporate Logo
T#:33412918
Part#: 12521732596
In Stock
Sale - Save 40% $ 10.99

This product was last offered at the strikethrough price on
11-07-2026

$ 6.59 USD
Free Shipping on orders $49 and up
Sale - Save 40%
$ 10.99

This product was last offered at the strikethrough price on
11-07-2026

$ 6.59 USD
Free Shipping on orders $49 and up

Includes connector housing with terminals and seals. Commonly used for the camshaft position sensor.

ECS Tuning replacement harness connectors include all necessary pins and wire seals for a complete harness repair. Whether you have a broken harness connector or need a complete wiring repair, we have the components you need.

Each connector includes an additional terminal in case one becomes lost or damaged during installation.

*OEM cross reference PN# 12521732596 - Commonly used for the camshaft position sensor.

Please reference the original part number from the existing connector to confirm fitment, before ordering.

Suggested tools:

Suggested crimping pliers: T#387193
Wire De-pin tools:
12pc De-Pin Tool Set - T#386379
23pc De-Pin Tool Set - T#641943

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3 Pin Connector
10X Entries Into Our F80 M3 Sweepstakes 10X Entries For Our Spin To Win Sweepstakes!
ECS - Corporate Logo
T#:33412947
Part#: 12521433916
In Stock
Sale - Save 40% $ 10.99

This product was last offered at the strikethrough price on
11-07-2026

$ 6.59 USD
Free Shipping on orders $49 and up
Sale - Save 40%
$ 10.99

This product was last offered at the strikethrough price on
11-07-2026

$ 6.59 USD
Free Shipping on orders $49 and up

Includes connector housing with terminals and seals. Commonly used for the crankshaft position sensor.

ECS Tuning replacement harness connectors include all necessary pins and wire seals for a complete harness repair. Whether you have a broken harness connector or need a complete wiring repair, we have the components you need.

Each connector includes an additional terminal in case one becomes lost or damaged during installation.

*OEM cross reference PN# 12521433916 - Commonly used for the crankshaft position sensor.

Please reference the original part number from the existing connector to confirm fitment, before ordering.

Suggested tools:

Suggested crimping pliers: T#387193
Wire De-pin tools:
12pc De-Pin Tool Set - T#386379
23pc De-Pin Tool Set - T#641943

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3 Pin Connector
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ECS - Corporate Logo
T#:33412924
Part#: 12521433917
Ships on Jan 28, 2027
Sale - Save 14% $ 8.99

This product was last offered at the strikethrough price on
10-28-2026

$ 7.69 USD
Free Shipping on orders $49 and up
Sale - Save 14%
$ 8.99

This product was last offered at the strikethrough price on
10-28-2026

$ 7.69 USD
Free Shipping on orders $49 and up

Includes connector housing with terminals and seals. Commonly used for the camshaft position sensor.

ECS Tuning replacement harness connectors include all necessary pins and wire seals for a complete harness repair. Whether you have a broken harness connector or need a complete wiring repair, we have the components you need.

Each connector includes an additional terminal in case one becomes lost or damaged during installation.

*OEM cross reference PN# 12521433917 - Commonly used for the camshaft position sensor.

Please reference the original part number from the existing connector to confirm fitment, before ordering.

Suggested tools:

Suggested crimping pliers: T#387193
Wire De-pin tools:
12pc De-Pin Tool Set - T#386379
23pc De-Pin Tool Set - T#641943

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3 Pin Connector
10X Entries Into Our F80 M3 Sweepstakes 10X Entries For Our Spin To Win Sweepstakes!
ECS - Corporate Logo
T#:33412925
Part#: 12521433915
In Stock
Sale - Save 40% $ 10.99

This product was last offered at the strikethrough price on
11-07-2026

$ 6.59 USD
Free Shipping on orders $49 and up
Sale - Save 40%
$ 10.99

This product was last offered at the strikethrough price on
11-07-2026

$ 6.59 USD
Free Shipping on orders $49 and up

Includes connector housing with terminals and seals. Commonly used for the engine oil level sensor.

ECS Tuning replacement harness connectors include all necessary pins and wire seals for a complete harness repair. Whether you have a broken harness connector or need a complete wiring repair, we have the components you need.

Each connector includes an additional terminal in case one becomes lost or damaged during installation.

*OEM cross reference PN# 12521433915 - Commonly used for the engine oil level sensor.

Please reference the original part number from the existing connector to confirm fitment, before ordering.

Suggested tools:

Suggested crimping pliers: T#387193
Wire De-pin tools:
12pc De-Pin Tool Set - T#386379
23pc De-Pin Tool Set - T#641943

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Precision Raceworks - Corporate Logo
T#:38161695
Part#: 201-0360-RED
Ships in 9 Business Days
$ 5.99 USD
Free Shipping on orders $49 and up
Upgrade any wiring system with this optimal solution, ensuring reliability and durability in any demanding automotive application. Red in color and 12 Gauge.

Precision Raceworks - Corporate Logo
T#:38161703
Part#: 201-0360-BLU
Ships in 9 Business Days
$ 4.99 USD
Free Shipping on orders $49 and up
Upgrade any wiring system with this optimal solution, ensuring reliability and durability in any demanding automotive application. Blue in color and 12 Gauge.

Precision Raceworks - Corporate Logo
T#:38161710
Part#: 201-0362
Ships in 9 Business Days
$ 4.99 USD
Free Shipping on orders $49 and up
Upgrade any wiring system with this optimal solution, ensuring reliability and durability in any demanding automotive application. Black in color and 18 Gauge dual wire.
Precision Raceworks - Corporate Logo
T#:38161711
Part#: 201-0360-BLK
Ships in 9 Business Days
$ 4.99 USD
Free Shipping on orders $49 and up
Upgrade any wiring system with this optimal solution, ensuring reliability and durability in any demanding automotive application. Black in color and 12 Gauge.

Precision Raceworks - Corporate Logo
T#:38161698
Part#: 201-0360-ORG
Ships in 9 Business Days
$ 4.99 USD
Free Shipping on orders $49 and up
Upgrade any wiring system with this optimal solution, ensuring reliability and durability in any demanding automotive application. Orange in color and 12 Gauge.
Precision Raceworks - Corporate Logo
T#:38161687
Part#: 201-0361-GRN
Ships in 9 Business Days
$ 3.99 USD
Free Shipping on orders $49 and up
Upgrade any wiring system with this optimal solution, ensuring reliability and durability in any demanding automotive application. Green in color and 18 Gauge.

Precision Raceworks - Corporate Logo
T#:38161693
Part#: 201-0360-WHT
Ships in 9 Business Days
$ 4.99 USD
Free Shipping on orders $49 and up
Upgrade any wiring system with this optimal solution, ensuring reliability and durability in any demanding automotive application. White in color and 12 Gauge.

Precision Raceworks - Corporate Logo
T#:38161692
Part#: 201-0360-YEL
Ships in 9 Business Days
$ 4.99 USD
Free Shipping on orders $49 and up
Upgrade any wiring system with this optimal solution, ensuring reliability and durability in any demanding automotive application. Yellow in color and 12 Gauge.
2 Pin Connector
10X Entries Into Our F80 M3 Sweepstakes 10X Entries For Our Spin To Win Sweepstakes!
ECS - Corporate Logo
T#:33412928
Part#: 12521427615
In Stock
Sale - Save 35% $ 7.99

This product was last offered at the strikethrough price on
11-07-2026

$ 5.19 USD
Free Shipping on orders $49 and up
Sale - Save 35%
$ 7.99

This product was last offered at the strikethrough price on
11-07-2026

$ 5.19 USD
Free Shipping on orders $49 and up
Includes connector housing with terminals and seals. Commonly used for the engine oil pressure switch. ECS Tuning replacement harness connectors include all necessary pins and wire seals for a complete harness repair. Whether you have a broken harness connector or need a complete wiring repair, we have the components you need. Each connector includes an additional terminal in case one becomes lost or damaged during installation. *OEM cross reference PN# 12521427615 - Commonly used for the engine oil pressure switch. Please reference the original part number from the existing connector to confirm fitment, before ordering. Suggested tools: Suggested crimping pliers: T#387193 Wire De-pin tools: 12pc De-Pin Tool Set - T#386379 23pc De-Pin Tool Set - T#641943
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2 Pin Connector
10X Entries Into Our F80 M3 Sweepstakes 10X Entries For Our Spin To Win Sweepstakes!
ECS - Corporate Logo
T#:33412932
Part#: 61132359999
In Stock
Sale - Save 40% $ 10.99

This product was last offered at the strikethrough price on
11-07-2026

$ 6.59 USD
Free Shipping on orders $49 and up
Sale - Save 40%
$ 10.99

This product was last offered at the strikethrough price on
11-07-2026

$ 6.59 USD
Free Shipping on orders $49 and up

Includes connector housing with terminals and seals. Commonly used for the coolant level sensor.

ECS Tuning replacement harness connectors include all necessary pins and wire seals for a complete harness repair. Whether you have a broken harness connector or need a complete wiring repair, we have the components you need.

Each connector includes an additional terminal in case one becomes lost or damaged during installation.

*OEM cross reference PN# 61132359999 - Commonly used for the coolant level sensor.

Please reference the original part number from the existing connector to confirm fitment, before ordering.

Suggested tools:

Suggested crimping pliers: T#387193
Wire De-pin tools:
12pc De-Pin Tool Set - T#386379
23pc De-Pin Tool Set - T#641943

Show More Show Less