This page lists 14 electrical switch & relay parts for the 2021 BMW M850I, across 6 part types, covering the 4.4L V8 Turbocharged engine. Every part shows its brand, manufacturer part number and fitment notes.
The switch and relay system on the 2021 BMW M850I covers the switches, relays and flashers that route power to everything the driver touches. The largest groups are Brake Light Switch (4 parts), A/C Refrigerant Pressure Switch (3 parts) and Oil Pressure Sender / Switch (3 parts). The other 3 part types cover the remaining 4 parts.
Every part on this page is matched to the 4.4L V8 Turbocharged — the only engine offered in the 2021 BMW M850I.
The most listed brands for 2021 BMW M850I electrical switch & relay parts are WELLS (5 parts), VEMO (2 parts) and STANDARD MOTOR PRODUCTS (2 parts), plus 5 more brands. Quality grades include Standard Replacement and Economy.
Each part number listed for the 2021 BMW M850I opens a page with every vehicle that part fits.
A/C Refrigerant Pressure Switch
| Brand | Part Number | Markets | Notes | Buy |
|---|---|---|---|---|
| FOUR SEASONS | 20997 | 🇺🇸 US 🇨🇦 CA 🇲🇽 MX | Pressure Switch | View on Amazon |
| REIN | ACS0243P | 🇺🇸 US 🇨🇦 CA 🇲🇽 MX | View on Amazon | |
| UAC | SW11170C | 🇺🇸 US 🇨🇦 CA 🇲🇽 MX | Pressure Transducer | View on Amazon |
This table covers the pressure switches on the A/C circuit. Typical signs include a function that works intermittently, or a click without the accessory coming on. Inspect the connector behind the switch; heat-damaged terminals will kill the new part too.
3 A/C Refrigerant Pressure Switch parts for the 2021 BMW M850I come from 3 brands — FOUR SEASONS, REIN and UAC.
Listed part numbers: FOUR SEASONS 20997, REIN ACS0243P and UAC SW11170C.
Brake Light Switch
Economy
| Brand | Part Number | Markets | Notes | Buy |
|---|---|---|---|---|
| VEMO | V20730151 | 🇺🇸 US 🇨🇦 CA 🇲🇽 MX | Base Model | View on Amazon |
Standard Replacement
| Brand | Part Number | Markets | Notes | Buy |
|---|---|---|---|---|
| BECK/ARNLEY | 2012711 | 🇺🇸 US 🇨🇦 CA 🇲🇽 MX | View on Amazon | |
| STANDARD MOTOR PRODUCTS | SLS541 | 🇺🇸 US 🇨🇦 CA 🇲🇽 MX | View on Amazon | |
| WELLS | 1S12667 | 🇺🇸 US 🇨🇦 CA 🇲🇽 MX | Convertible or Sedan | View on Amazon |
This table covers the pedal-mounted switch that turns on the brake lamps. Typical signs include a function that works intermittently, or a click without the accessory coming on. Inspect the connector behind the switch; heat-damaged terminals will kill the new part too.
4 Brake Light Switch parts for the 2021 BMW M850I come from 4 brands — VEMO, BECK/ARNLEY, STANDARD MOTOR PRODUCTS and 1 other brand.
The Economy section lists 1 option from VEMO — the catalog's value-priced group. VEMO V20730151 is listed in this group.
In the Standard Replacement grade, BECK/ARNLEY, STANDARD MOTOR PRODUCTS and WELLS supply 3 parts: built to original-equipment specification. A representative part number is BECK/ARNLEY 2012711.
Listed part numbers: VEMO V20730151, BECK/ARNLEY 2012711 and STANDARD MOTOR PRODUCTS SLS541, plus the other parts above.
Headlamp Switch
| Brand | Part Number | Markets | Notes | Buy |
|---|---|---|---|---|
| WELLS | 1S18213 | 🇺🇸 US 🇨🇦 CA 🇲🇽 MX | M850i xDrive Gran Coupewith Night Vision Camera | View on Amazon |
| WELLS | 1S18220 | 🇺🇸 US 🇨🇦 CA 🇲🇽 MX | M850i xDrive Gran Coupewithout Night Vision Camera | View on Amazon |
This table covers the column or dash switches that control the exterior lamps. Typical signs include a function that works intermittently, or a click without the accessory coming on. Inspect the connector behind the switch; heat-damaged terminals will kill the new part too.
WELLS supplies both parts for the 2021 BMW M850I.
Listed part numbers: WELLS 1S18213 and WELLS 1S18220.
Oil Pressure Sender / Switch
| Brand | Part Number | Markets | Notes | Buy |
|---|---|---|---|---|
| FACET | 250015 | 🇺🇸 US 🇨🇦 CA 🇲🇽 MX | View on Amazon | |
| STANDARD MOTOR PRODUCTS | PS754 | 🇺🇸 US 🇨🇦 CA 🇲🇽 MX | M850i xDrive Gran Coupewith Light | View on Amazon |
| WELLS | 1S16103 | 🇺🇸 US 🇨🇦 CA 🇲🇽 MX | View on Amazon |
This table covers the senders and switches that report oil pressure to the gauge or lamp. Typical signs include a lamp that stays on, or a gauge that never moves. Confirm power and ground at the connector before replacing the sender or switch.
3 Oil Pressure Sender / Switch parts for the 2021 BMW M850I come from 3 brands — FACET, STANDARD MOTOR PRODUCTS and WELLS.
Part numbers include FACET 250015, STANDARD MOTOR PRODUCTS PS754 and WELLS 1S16103.
Power Window Switch
| Brand | Part Number | Markets | Notes | Buy |
|---|---|---|---|---|
| VEMO | V20730271 | 🇺🇸 US 🇨🇦 CA 🇲🇽 MX | Fits RearM850i xDrive Base Model | View on Amazon |
This table covers the switches that command each window motor. Typical signs include a function that works intermittently, or a click without the accessory coming on. Inspect the connector behind the switch; heat-damaged terminals will kill the new part too.
This group shows a single part: VEMO V20730271.
Turn Signal Switch
| Brand | Part Number | Markets | Notes | Buy |
|---|---|---|---|---|
| WELLS | 1S17939 | 🇺🇸 US 🇨🇦 CA 🇲🇽 MX | View on Amazon |
This table covers the combination / turn-signal switches. Typical signs include a function that works intermittently, or a click without the accessory coming on. Inspect the connector behind the switch; heat-damaged terminals will kill the new part too.
This group shows a single part: WELLS 1S17939.
Buying Electrical Switch & Relay Parts for a 2021 BMW M850I
On this vehicle, the switch and relay system covers the switches, relays and flashers that route power to everything the driver touches.
- Confirm you have the 4.4L V8 Turbocharged engine — every part on this page is matched to it.
- Read the notes on each row for position, trim and spec qualifiers before you order.
- Where labor overlaps, inspect the connector terminals behind any failed switch — heat damage there will kill the new part too.
- Cross-reference the manufacturer part number against your old part or a service-manual listing.
Start with the largest groups on this page: Brake Light Switch and A/C Refrigerant Pressure Switch .
Frequently Asked Questions
How many electrical switch & relay parts fit the 2021 BMW M850I?
Our catalog currently lists 14 electrical switch & relay parts for the 2021 BMW M850I across 6 subcategories and 8 brands, covering the 4.4L V8 Turbocharged engine. Each part is matched to the engine(s) it fits.
What are the signs of electrical switch & relay problems on a 2021 BMW M850I?
Common symptoms include accessories that work intermittently, a click without action, or one function dead while its fuse tests fine. If you notice any of these, identify the affected subcategory above and cross-reference the part numbers listed.
What should I replace at the same time?
Where labor overlaps, inspect the connector terminals behind any failed switch — heat damage there will kill the new part too.
What do the market flags (US, CA, MX) on each part mean?
They show the market for which the manufacturer published application data for that part — where the vehicle was first sold, not where the part was made. If your 2021 BMW M850I was originally sold in the US, the safest choice is a part marked for the US market.
How do I make sure a part fits my 2021 BMW M850I?
Every part on this page is matched to the 4.4L V8 Turbocharged engine. Then swap a suspect relay with an identical known-good one from the fuse box before buying — it is the fastest diagnostic there is. The notes column carries position and trim qualifiers where they apply.
Other Parts for the 2021 BMW M850I
Electrical Switch & Relay Parts for Other BMW M850I Years
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Manufacturer names, model designations and part numbers are used for identification and fitment reference only. AutoFactsDB is an independent catalog and is not affiliated with, endorsed by, or sponsored by any vehicle manufacturer displayed on this page.