BMW Electrical Sensors, Switches, & Relays for BMW 5 Series E39 (1996-2003)

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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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Turner Alpha-N IAT Sensor Relocation Kit - S54 S62 S85
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Turner Motorsport - Corporate Logo
T#:597496
Part#: 014579TMSKT
In Stock
Sale - Save 35% $ 130.96
$ 85.12 USD
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Sale - Save 35% $ 130.96
$ 85.12 USD
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Turner Plug-and-Play IAT Relocation Kit
For vehicles with production date from 09/1998
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Turner Motorsport - Corporate Logo
T#:391751
Part#: 014579TMS
In Stock
Sale - Save 28% $ 201.99
Starting at $ 145.57 USD
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Sale - Save 28% $ 201.99
Starting at $ 145.57 USD
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All vehicles will lose some degree of performance due to heat soak under the right operating conditions.  Engine management systems constantly monitor operating conditions and modifying parameters based on sensor inputs. BMW integrated the intake air temp sensor in the MAF housing on models such as the E39 M5, and, being sandwiched behind a hot radiator and in some applications next to an even hotter valve cover, this is less than ideal for performance applications. Absorbing excess heat from its surroundings, the MAF can’t shed it fast enough, and the ECU reads an inaccurately high intake air temperature. Compensating for this false hot air measurement, the ECU pulls timing and runs a richer fuel mixture, resulting in a significant loss of torque.

What can you do?  Locate an intake air temp sensor in a location where it can properly measure incoming air temps and where it's less prone to heat soak. Mounting the sensor further away from the heat source and isolating it from the MAF housing, it can both resist the effects of heat soak longer and respond to temperature changes more quickly.  The result is you’ll experience reduced torque loss and more consistent power output when you’re pushing your engine hard. 

The Turner engineering team was initially skeptical of the claimed performance benefits of this modification. They first set out validate the functionality and performance benefit of a temp sensor relocation. Replicating stop-and-go traffic heat soak in a 2001 540i was a simple task in a controlled environment - their dynometer. First the car was heat soaked to simulate being stuck in traffic or moving at low speeds by running the car four times on the dyno with the dyno's cooling fans disabled. The fans were then turned on for three more runs to observe the recovery rate once air flow was reintroduced. The test: following this procedure once with a stock IAT, and once with their relocation kit in place. 

The result? Turner recovered 11lb-ft torque at 2500rpm through use of their relocation kit, with even greater recovery to be found for M5 owners. Here are the heat soak-related torque losses Turner experienced:

Stock IAT location:
18rwtq at 2500rpm
10rwtq at 3000rpm
9rwtq at 3700rpm

Turner IAT Relocation:
7rwtq at 2500rpm
5rwtq at 3000rpm
5rwtq at 3700rpm

**Click here for installation instructions**

The Turner engineering team designed a complete plug and play kit (unlike all other options on the market) that makes for quick, easy, and reversible installation. Weather-sealed connectors keep out the elements, while sheathed wiring offers a clean appearance underhood. With a harness nearly 3 feet long - the Turner IAT relocation kit offers flexibility in positioning, but not too long that you're left with unsightly excess wiring. Turner recommends positioning the sensor in a location away from engine heat, but still within the intake ducting to achieve accurate intake temp readings - such as the far side of the base of the airbox. Vehicles with cold air intakes with cone-style filters can even position the sensor in the end of the filter. Simply drill a hole in your (cool) location of choice and plug in the harness. More information including installation instructions and some good examples of sensor mounting locations can be found in our DIY PDF. 

We include everything you need to relocate your IAT, just select your desired sensor brand below - Genuine BMW or original equipment Beru.

Also the perfect plug-n-play option for anyone looking to upgrade their intake to utilize an Alpha-N tune!

Note for vehicles with M62 engine: applicable to 1999 and up

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Turner Plug-And-Play Alpha-N IAT Sensor Relocation Kit
10X Entries For Our Spin To Win Sweepstakes!
Turner Motorsport - Corporate Logo
T#:638071
Part#: 014579TMSKT1
In Stock
Sale - Save 40% $ 142.99
$ 85.79 USD
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Sale - Save 40% $ 142.99
$ 85.79 USD
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What can you do to get rid of this heat soak? Turner designed an IAT relocation kit that moves the intake air temp sensor to a cooler location. Mounting the sensor further away from the heat source and isolating it from the MAF housing, it can both resist the effects of heat soak longer and respond to temperature changes more quickly. The result is you’ll experience reduced torque loss and more consistent power output when you’re pushing your engine hard.
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Turner Motorsport Oil Temperature Sensor Flange
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Turner Motorsport - Corporate Logo
T#:359474
Part#: TEN9990001
In Stock
Sale - Save 57% $ 100.99
$ 42.99 USD
Limited Qty Sale
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Sale - Save 57% $ 100.99
$ 42.99 USD
Limited Qty Sale
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The Turner Motorsport Oil Temperature Sensor Flange was designed to get your oil temperature from the best possible location: the sump. Most of the factory and aftermarket sensors are located after the oil pump, which does not give you an accurate temp reading of the oil that is actually lubricating the engine. At the factory temp sensor location the sensor picks up heat not only from the oil stream, but also from the oil pump and housing which will skew the reading. Other aftermarket adapters can be give inaccurate readings from their location and/or design limitations. And may require making unnecessary modifications. By relocating the sensor to the oil sump it reduces clutter and sits flush against the bottom of the oil pan to avoid potential clearance issues. Testing that we have done on and off the track shows that the sump location is the most accurate. We accomplish this by removing the factory oil level sensor or block off plate and using the existing hole and bolt pattern on the oil pan with no additional modifications. Any sensor with an M12 x 1.50mm thread can be used in the flange. 

Note that removing the factory oil level sensor will trigger the low oil fault/warning light. There's no elegant way around this but since the Temp Flange is considered a race-only part we assume you will be checking your own oil level anyway or be using a stand-alone dash/engine management system that does not track oil level. And having the most accurate oil temp is more important.

Applications:
1987-1991 E30 M3
1992-1999 3 Series E36 M3 3.0 and M3 3.2 Euro Models Only!
1999-2006 3 Series E46 All
1991-1995 5 Series E34 525i M50
1997-2003 5 Series E39 525i, 528i, 530i, 540i, 540iP, M5
2004-xxxx 5 Series E60 525i, 530i
1995-2001 7 Series E38 
Z3 2.5, 2.5i, 2.8, 3.0i, M3.2 S54
Z4 2.5, 3.0
Z8 All

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Braille - Corporate Logo
T#:558037
Part#: B14115
Ships in 4 Business Days
$ 204.99 USD
Free Shipping on orders $49 and up
When building a car for the track, one of the most important factors to consider is weight. Stock batteries can weigh up to almost 50 pounds and are unnecessarily large, designed to power a host of systems not normally used in a track car (radios, lighting, etc.). What can you do to cut weight the weight without affecting your cars operation? This is where Braille Battery comes in with their long line of performance lightweight battery options! Designed to provide the highest cranking power possible while being up to 75% lighter, Braille Battery is one of the foremost leaders in automotive racing batteries with nothing but high quality, high output batteries in mind!
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Braille - Corporate Logo
T#:558042
Part#: B3121
Ships in 5 Business Days
$ 270.99 USD
Free Shipping on orders $49 and up
When building a car for the track, one of the most important factors to consider is weight. Stock batteries can weigh up to almost 50 pounds and are unnecessarily large, designed to power a host of systems not normally used in a track car (radios, lighting, etc.). What can you do to cut weight the weight without affecting your car's operation? This is where Braille Battery comes in with their long line of performance lightweight battery options! Designed to provide the highest cranking power possible while being up to 75% lighter, Braille Battery is one of the foremost leaders in automotive racing batteries with nothing but high quality, high output batteries in mind! The B3121 battery from Braille is their lightest do-everything battery available, offering 1380 pulse cranking amps that can crank over V8 engines with ease while still coming in at under 22 pounds, half of the weight of a standard Group 34 battery! This is thanks to their Advanced AGM racing technology that allows them to put a ton of power into a very small package. Physical Specifications: BCI Group: All sizes Weight: 21lbs / 9.5kg Length: 6.6" / 168mm Width: 5.2" / 132mm Height: 6.8" / 173mm Polarity: Right Side Positive Terminal Type: Steel terminal block with M6 bolt Performance Specifications: Voltage: 12v Recharge Voltage: 14.4V – 14.6V Maintenance charge voltage: 13.8V 5s Pulse Cranking Amps (PCA): 1380 10s PDC: 124 Amp Hour (Ah): 31 Watt Hour (Wh): 372 Life Cycle @ 10% DOD: 3100 Charging Temperature 0C to 50C Discharge Temperature range -40C to +60C Storage temperature -40C to +60C *THIS BATTERY REQUIRES A CUSTOM MOUNTING SOLUTION. The size and weight are significantly smaller than a stock battery and will not be held in place by the stock battery mount*
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Braille - Corporate Logo
T#:558038
Part#: B2015
Ships in 4 Business Days
$ 237.99 USD
Free Shipping on orders $49 and up
When building a car for the track, one of the most important factors to consider is weight. Stock batteries can weigh up to almost 50 pounds and are unnecessarily large, designed to power a host of systems not normally used in a track car (radios, lighting, etc.). What can you do to cut weight the weight without affecting your cars operation? This is where Braille Battery comes in with their long line of performance lightweight battery options! Designed to provide the highest cranking power possible while being up to 75% lighter, Braille Battery is one of the foremost leaders in automotive racing batteries with nothing but high quality, high output batteries in mind! The B2015 is Braille's most popular non-carbon racing battery and is able to start larger engines easily for racing and offers daily driving capability for most 4 and 6 cylinders engine vehicles. Physical Specifications: BCI Group: All sizes Weight: 15lbs / 6.8kg Length: 6.8" / 173mm Width: 3.4" / 86mm Height: 6.1" / 155mm Polarity: Right Side Positive Performance Specifications: Voltage: 12 Full Charge Voltage: 13.2 Pulse Cranking Amps (PCA): 1067 Amp Hour (AH): 21 Life Cycle @ 10% DOD: 3100 *THIS BATTERY REQUIRES A CUSTOM MOUNTING SOLUTION. The size and weight are significantly smaller than a stock battery and will not be held in place by the stock battery mount*
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Braille Performance Endurance AGM Battery - B10049 - 58lbs
This item is classified as Hazardous Materials and requires special shipping and handling. We cannot ship this item out of the US or with priority shi
Braille - Corporate Logo
T#:558078
Part#: B10049
Ships in 5 Business Days
$ 446.99 USD
$ 446.99 USD
This Group 49 Endurance AGM battery is an ideal upgrade from the factory battery, offering higher cranking power and a longer battery life for less waste and lower cost to the customer. Plus, this battery is maintenance free and won't eat holes in the battery tray and surrounding areas of your car. Endurance AGM batteries from Braille are a drop-in OEM replacement that requires no modifications to be made for installation, has the highest cranking power and longest run times in their class, and also feature AGM internal racing technology developed for their Advanced AGM and Carbon Fiber batteries.
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Braille - Corporate Logo
T#:558046
Part#: G30
Ships on Jul 15, 2025
$ 522.99 USD
Free Shipping on orders $49 and up
The G30 lithium battery from Braille is designed for the Import Tuner market (4 and 6 cylinder) for track use and has enough power for small black V8 race cars and hot rods with light electrical demands/accessories and standard compression. The G30 comes in the popular ETX 30 Group size, just like the B3121 AGM, so it is small and light enough to mount in a variety of locations. Incorporated in this battery is the same technology used in their race winning batteries used by nearly every OEM developer in classes ranging from SCCA to Formula 1.
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Performance Tool - Corporate Logo
T#:1809154
Part#: W5368
Ships in 1 Business Day
$ 15.99 USD
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A must for any toolbox.