12 Electrical switch & relay parts are listed for the 2021 BMW 840I, in 6 part types, covering the 3.0L L6 Turbocharged engine. Each one has a brand, a manufacturer part number and notes that say where it fits.
The switch and relay system on the 2021 BMW 840I covers the switches, relays and flashers that route power to everything the driver touches. The largest groups are Oil Pressure Sender / Switch (4 parts), A/C Refrigerant Pressure Switch (3 parts) and Headlamp Switch (2 parts). The other 3 part types cover the remaining 3 parts.
Every part on this page is matched to the 3.0L L6 Turbocharged — the only engine offered in the 2021 BMW 840I.
The most listed brands for 2021 BMW 840I electrical switch & relay parts are WELLS (6 parts), FOUR SEASONS (1 part) and REIN (1 part), plus 4 more brands.
Each part number listed for the 2021 BMW 840I opens a page with every vehicle that part fits.
A/C Refrigerant Pressure Switch
| Brand | Part Number | Markets | Notes | Buy |
|---|---|---|---|---|
| FOUR SEASONS | 20997 | 🇺🇸 US | Pressure Switch | View on Amazon |
| REIN | ACS0243P | 🇺🇸 US | View on Amazon | |
| UAC | SW11170C | 🇺🇸 US | 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 840I come from 3 brands — FOUR SEASONS, REIN and UAC.
Part numbers include FOUR SEASONS 20997, REIN ACS0243P and UAC SW11170C.
Headlamp Switch
| Brand | Part Number | Markets | Notes | Buy |
|---|---|---|---|---|
| WELLS | 1S18213 | 🇺🇸 US | 840i Base Model or 840i xDrive Base Modelwith Night Vision Camera | View on Amazon |
| WELLS | 1S18220 | 🇺🇸 US | 840i Base Model or 840i xDrive Base Modelwithout 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 840I.
This group includes WELLS 1S18213 and WELLS 1S18220.
Ignition Starter Switch
| Brand | Part Number | Markets | Notes | Buy |
|---|---|---|---|---|
| WELLS | 1S17908 | 🇺🇸 US | Fits 840i Base Model or 840i xDrive Base Modelwith Push Button Switch, with Class Packag | View on Amazon |
This table covers the ignition switches that feed the starter 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.
One part is listed for the 2021 BMW 840I — WELLS 1S17908.
Oil Pressure Sender / Switch
| Brand | Part Number | Markets | Notes | Buy |
|---|---|---|---|---|
| GPD | 1816559 | 🇺🇸 US | with Light | View on Amazon |
| STANDARD MOTOR PRODUCTS | PS754 | 🇺🇸 US | 840i xDrive Gran Coupewith Light | View on Amazon |
| WELLS | 1S16103 | 🇺🇸 US | 840i xDrive Base Model | View on Amazon |
| WELLS | 1S15907 | 🇺🇸 US | 840i Base Model | 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.
4 Oil Pressure Sender / Switch parts for the 2021 BMW 840I come from 3 brands — WELLS, GPD and STANDARD MOTOR PRODUCTS.
This group includes GPD 1816559, STANDARD MOTOR PRODUCTS PS754 and WELLS 1S16103 and the remaining parts above.
Power Window Switch
| Brand | Part Number | Markets | Notes | Buy |
|---|---|---|---|---|
| VEMO | V20730271 | 🇺🇸 US | RightColor: Black | 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 | 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 840I
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 3.0L L6 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: Oil Pressure Sender / Switch and A/C Refrigerant Pressure Switch .
Frequently Asked Questions
How many electrical switch & relay parts fit the 2021 BMW 840I?
Our catalog currently lists 12 electrical switch & relay parts for the 2021 BMW 840I across 6 subcategories and 7 brands, covering the 3.0L L6 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 840I?
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 840I 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 840I?
Every part on this page is matched to the 3.0L L6 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 840I
Electrical Switch & Relay Parts for Other BMW 840I 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.