BMW Electrical Sensors, Switches, & Relays for BMW 3 Series E30 (1984-1991)

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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 - 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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Race German - Corporate Logo
T#:2602229
Part#: E30FUSEKIT
Ships in 1 Business Day
$ 35.99 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
Innovate Motorsports - Corporate Logo
T#:28836410
Part#: 38770
In Stock at Vendor
$ 212.99 USD
Free Shipping on orders $49 and up

Features & Benefits:

Two configurable linear 0-5V analog outputs Ability to calibrate O2 sensors for maximum accuracy Includes LC-2 controller and Bosch wideband O2 sensor Comes with a program cable, manual, and a 10 ft. sensor cable Includes a 1-inch mild steel exhaust bung Innovate MTS serial in/out capability Integrated dual-color status LED (green/red) Patented DirectDigital™ wideband sensor control Positive lock connectors for all connections Real-time display data on screen or with the powerful LogWorks software Range:

AFR (Air-Fuel Ratio) range from 7.4:1 to 22.4:1 (0.5 to 1.5 lambda)

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Race German - Corporate Logo
T#:6827884
Part#: C101-HOLDER
Ships in 2 Business Days
$ 44.99 USD
Free Shipping on orders $49 and up
Race German has devoted themselves to providing quality products for late model BMWs that cover both street and track applications. Race German has now grown their catalog to a wide variety of models and products geared towards keeping your car looking and running nice. BMW's original C101 bracket which connects to the firewall and holds the diagnosis port unfortunately over time becomes heat soaked and brittle. The OEM bracket, which is no longer available, also features a flawed hinge design that easily wears and breaks. Race German has devised a solution to this issue and developed a new bracket! This heavy duty C101 firewall bracket is completely plug and play. These brackets are CAD designed and feature a two piece design with stainless steel hardware.
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ECS - Corporate Logo
T#:40072446
Part#: LK2M
In Stock
Sale - Save 29% $ 6.99

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

$ 4.94 USD
Free Shipping on orders $49 and up
Sale - Save 29%
$ 6.99

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

$ 4.94 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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ECS - Corporate Logo
T#:33412930
Part#: 12521706096
In Stock
Sale - Save 11% $ 10.99

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

$ 9.78 USD
Free Shipping on orders $49 and up
Sale - Save 11%
$ 10.99

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

$ 9.78 USD
Free Shipping on orders $49 and up

Includes connector housing with terminals and seals. Commonly used for the idle air control valve (IACV).

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# 12521706096 - Commonly used for the idle air control valve (IACV).

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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ECS - Corporate Logo
T#:33412932
Part#: 61132359999
Ships in 5 Business Days
Sale - Save 25% $ 10.99

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

$ 8.24 USD
Free Shipping on orders $49 and up
Sale - Save 25%
$ 10.99

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

$ 8.24 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