This page lists 25 electrical switch & relay parts for the 2021 Audi A8, across 15 part types, covering all 3 engine options (3.0L V6 ELECTRIC/GAS Turbocharged, 3.0L V6 Turbocharged and 4.0L V8 Turbocharged). Every part shows its brand, manufacturer part number and fitment notes.
On the 2021 Audi A8, the switch and relay system covers the switches, relays and flashers that route power to everything the driver touches. Most of the listed parts are Oil Pressure Sender / Switch (8 parts), A/C Refrigerant Pressure Switch (3 parts) and Power Window Switch (2 parts). The other 12 part types cover the remaining 12 parts.
The 2021 Audi A8 was sold with 3 engines. 3 parts fit every engine; the other 22 are engine-specific. Each part shows which engine(s) it fits.
10 brands supply electrical switch & relay parts for the 2021 Audi A8, led by HELLA (6 parts), VEMO (6 parts) and WELLS (4 parts), plus 7 more brands. Quality grades include Standard Replacement and Economy.
A "Popular" badge means the source catalog flagged the part as frequently chosen for the 2021 Audi A8. 1 part has it: HELLA 003259971 (Oil Pressure Sender / Switch). Each part number opens a page with every vehicle that part fits.
A/C Condenser Fan Motor Relay
| Brand | Part Number | Markets | Notes | Buy |
|---|---|---|---|---|
| HELLA Fits: all 2021 A8 engines | 933332451 | 🇺🇸 US 🇨🇦 CA 🇲🇽 MX | 4-pin connector | View on Amazon |
This table covers the relays that control the A/C Condenser Fan Motor circuit. Typical signs include a click with no action, or a circuit that works only when you swap in a known-good relay. Swap with an identical relay in the fuse box before buying — it is the fastest test there is.
One part is listed for the 2021 Audi A8 — HELLA 933332451.
A/C Pressure Safety Switch
| Brand | Part Number | Markets | Notes | Buy |
|---|---|---|---|---|
| VEMO Fits: 3.0L V6 ELECTRIC/GAS Turbocharged | V10730521 | 🇺🇸 US 🇨🇦 CA | with Seal Ring | View on Amazon |
This table covers the A/C Pressure Safety 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: VEMO V10730521.
A/C Refrigerant Pressure Switch
| Brand | Part Number | Markets | Notes | Buy |
|---|---|---|---|---|
| FOUR SEASONS Fits: all 2021 A8 engines | 37427 | 🇺🇸 US 🇨🇦 CA 🇲🇽 MX | Pressure Switch | View on Amazon |
| UAC Fits: 3.0L V6 ELECTRIC/GAS Turbocharged, 3.0L V6 Turbocharged | SW11103C | 🇺🇸 US 🇨🇦 CA 🇲🇽 MX | Pressure Transducer | View on Amazon |
| UAC Fits: 4.0L V8 Turbocharged | SW11224C | 🇺🇸 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 are listed for the 2021 Audi A8, from UAC and FOUR SEASONS. 1 part fits every engine; the other 2 are engine-specific.
Part numbers include FOUR SEASONS 37427, UAC SW11103C and UAC SW11224C.
A/C Thermo Switch
| Brand | Part Number | Markets | Notes | Buy |
|---|---|---|---|---|
| GPD Fits: all 2021 A8 engines | 1713414 | 🇺🇸 US 🇨🇦 CA 🇲🇽 MX | Thermistor | View on Amazon |
This table covers the A/C Thermo 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: GPD 1713414.
Accessory Power Relay
| Brand | Part Number | Markets | Notes | Buy |
|---|---|---|---|---|
| HELLA Fits: 3.0L V6 ELECTRIC/GAS Turbocharged, 3.0L V6 Turbocharged | 933332451 | 🇺🇸 US 🇨🇦 CA 🇲🇽 MX | 4-pin connector | View on Amazon |
This table covers the relays that control the Accessory Power circuit. Typical signs include a click with no action, or a circuit that works only when you swap in a known-good relay. Swap with an identical relay in the fuse box before buying — it is the fastest test there is.
This group shows a single part: HELLA 933332451.
Brake Light Switch
| Brand | Part Number | Markets | Notes | Buy |
|---|---|---|---|---|
| WELLS Fits: 3.0L V6 ELECTRIC/GAS Turbocharged, 3.0L V6 Turbocharged | 1S14224 | 🇺🇸 US 🇨🇦 CA 🇲🇽 MX | 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.
One part is listed for the 2021 Audi A8 — WELLS 1S14224.
Fog / Driving Lamp Relay
| Brand | Part Number | Markets | Notes | Buy |
|---|---|---|---|---|
| HELLA Fits: 3.0L V6 ELECTRIC/GAS Turbocharged, 3.0L V6 Turbocharged | 933332451 | 🇺🇸 US 🇨🇦 CA 🇲🇽 MX | 4-pin connector | View on Amazon |
This table covers the relays that control the Fog / Driving Lamp circuit. Typical signs include a click with no action, or a circuit that works only when you swap in a known-good relay. Swap with an identical relay in the fuse box before buying — it is the fastest test there is.
One part is listed for the 2021 Audi A8 — HELLA 933332451.
Fuel Pump / Circuit Opening Relay
| Brand | Part Number | Markets | Notes | Buy |
|---|---|---|---|---|
| HELLA Fits: 3.0L V6 ELECTRIC/GAS Turbocharged, 3.0L V6 Turbocharged | 933332451 | 🇺🇸 US 🇨🇦 CA 🇲🇽 MX | 4-pin connector | View on Amazon |
This table covers the relays that control the Fuel Pump / Circuit Opening circuit. Typical signs include a click with no action, or a circuit that works only when you swap in a known-good relay. Swap with an identical relay in the fuse box before buying — it is the fastest test there is.
One part is listed for the 2021 Audi A8 — HELLA 933332451.
Horn Relay
| Brand | Part Number | Markets | Notes | Buy |
|---|---|---|---|---|
| WELLS Fits: 3.0L V6 ELECTRIC/GAS Turbocharged, 3.0L V6 Turbocharged | 1R2303 | 🇺🇸 US 🇨🇦 CA 🇲🇽 MX | Mounting Hardware Included: No | View on Amazon |
This table covers the relays that control the Horn circuit. Typical signs include a click with no action, or a circuit that works only when you swap in a known-good relay. Swap with an identical relay in the fuse box before buying — it is the fastest test there is.
This group shows a single part: WELLS 1R2303.
Multi-Function Relay
| Brand | Part Number | Markets | Notes | Buy |
|---|---|---|---|---|
| WELLS Fits: 3.0L V6 ELECTRIC/GAS Turbocharged, 3.0L V6 Turbocharged | 1R1007 | 🇺🇸 US 🇨🇦 CA 🇲🇽 MX | Mounting Hardware Included: No | View on Amazon |
This table covers the relays that control the Multi-Function circuit. Typical signs include a click with no action, or a circuit that works only when you swap in a known-good relay. Swap with an identical relay in the fuse box before buying — it is the fastest test there is.
One part is listed for the 2021 Audi A8 — WELLS 1R1007.
Oil Pressure Sender / Switch
Economy
| Brand | Part Number | Markets | Notes | Buy |
|---|---|---|---|---|
| WALKER PRODUCTS Fits: 3.0L V6 ELECTRIC/GAS Turbocharged, 3.0L V6 Turbocharged | 2561150 | 🇺🇸 US 🇨🇦 CA 🇲🇽 MX | View on Amazon |
Standard Replacement
| Brand | Part Number | Markets | Notes | Buy |
|---|---|---|---|---|
| HELLA Popular Fits: 3.0L V6 ELECTRIC/GAS Turbocharged, 3.0L V6 Turbocharged | 003259971 | 🇺🇸 US 🇨🇦 CA | 1-Pin ConnectorColor: Black or Turquoise | View on Amazon |
| FACET Fits: 3.0L V6 ELECTRIC/GAS Turbocharged, 3.0L V6 Turbocharged | 250053 | 🇺🇸 US 🇨🇦 CA 🇲🇽 MX | View on Amazon | |
| ROSTRA Fits: 3.0L V6 ELECTRIC/GAS Turbocharged, 3.0L V6 Turbocharged | 501543 | 🇺🇸 US 🇨🇦 CA 🇲🇽 MX | View on Amazon | |
| STANDARD MOTOR PRODUCTS Fits: 3.0L V6 ELECTRIC/GAS Turbocharged, 3.0L V6 Turbocharged | PS778 | 🇺🇸 US 🇨🇦 CA 🇲🇽 MX | Connector Type: Plug InFinish: Metal, Plastic | View on Amazon |
| WELLS Fits: 3.0L V6 ELECTRIC/GAS Turbocharged, 3.0L V6 Turbocharged | 1S12102 | 🇺🇸 US 🇨🇦 CA 🇲🇽 MX | 0.3 - 0.6 BarGreen | View on Amazon |
| Brand | Part Number | Markets | Notes | Buy |
|---|---|---|---|---|
| GPD Fits: 3.0L V6 ELECTRIC/GAS Turbocharged, 3.0L V6 Turbocharged | 1816565 | 🇺🇸 US 🇨🇦 CA 🇲🇽 MX | View on Amazon | |
| VEMO Fits: 3.0L V6 ELECTRIC/GAS Turbocharged, 3.0L V6 Turbocharged | V10730311 | 🇺🇸 US 🇨🇦 CA | 3 PINS | 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.
8 Oil Pressure Sender / Switch parts are listed for the 2021 Audi A8, from WALKER PRODUCTS, HELLA, FACET and 5 other brands. HELLA 003259971 carries the "Popular" badge.
In the Economy grade, WALKER PRODUCTS supplies 1 part: the catalog's value-priced group. A representative part number is WALKER PRODUCTS 2561150.
The Standard Replacement section lists 5 options from HELLA, FACET, ROSTRA and 2 other brands — built to original-equipment specification. HELLA 003259971 is listed in this group.
2 ungrouped parts are not assigned to a grade, with the same engine-level match.
Listed part numbers: HELLA 003259971, WALKER PRODUCTS 2561150 and FACET 250053, plus the other parts above.
Power Window Switch
| Brand | Part Number | Markets | Notes | Buy |
|---|---|---|---|---|
| VEMO Fits: 3.0L V6 ELECTRIC/GAS Turbocharged, 3.0L V6 Turbocharged | V10730719 | 🇺🇸 US 🇨🇦 CA | Fits Front Right | View on Amazon |
| VEMO Fits: 3.0L V6 ELECTRIC/GAS Turbocharged, 3.0L V6 Turbocharged | V10730728 | 🇺🇸 US 🇨🇦 CA | Front LeftSwitch Panel Assembly | 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.
VEMO supplies both parts for the 2021 Audi A8.
This group includes VEMO V10730719 and VEMO V10730728.
Radiator Fan Relay
| Brand | Part Number | Markets | Notes | Buy |
|---|---|---|---|---|
| HELLA Fits: 3.0L V6 ELECTRIC/GAS Turbocharged, 3.0L V6 Turbocharged | 933332451 | 🇺🇸 US 🇨🇦 CA 🇲🇽 MX | 4-pin connector | View on Amazon |
This table covers the relays that control the Radiator Fan circuit. Typical signs include a click with no action, or a circuit that works only when you swap in a known-good relay. Swap with an identical relay in the fuse box before buying — it is the fastest test there is.
This group shows a single part: HELLA 933332451.
Trunk Lid / Tailgate Release Switch
| Brand | Part Number | Markets | Notes | Buy |
|---|---|---|---|---|
| VEMO Fits: 3.0L V6 ELECTRIC/GAS Turbocharged, 3.0L V6 Turbocharged | V10730458 | 🇺🇸 US 🇨🇦 CA 🇲🇽 MX | View on Amazon |
This table covers the Trunk Lid / Tailgate Release 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: VEMO V10730458.
Turn Signal Switch
| Brand | Part Number | Markets | Notes | Buy |
|---|---|---|---|---|
| VEMO Fits: 3.0L V6 ELECTRIC/GAS Turbocharged, 3.0L V6 Turbocharged | V10800003 | 🇺🇸 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.
One part is listed for the 2021 Audi A8 — VEMO V10800003.
Buying Electrical Switch & Relay Parts for a 2021 Audi A8
On this vehicle, the switch and relay system covers the switches, relays and flashers that route power to everything the driver touches.
- Match the engine first. Some electrical switch & relay parts fit every engine; others are engine-specific. Each row shows which engine(s) it fits.
- 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 Audi A8?
Our catalog currently lists 25 electrical switch & relay parts for the 2021 Audi A8 across 15 subcategories and 10 brands, covering all 3 engine options (3.0L V6 ELECTRIC/GAS Turbocharged, 3.0L V6 Turbocharged and 4.0L V8 Turbocharged). Each part is matched to the engine(s) it fits.
Do electrical switch & relay parts differ between 2021 Audi A8 engines?
Some do. 3 parts fit every engine; the other 22 are engine-specific. Each row (and the filter at the top) shows which. If you're unsure which engine you have, check the emissions label under the hood or the 8th character of your VIN.
What are the signs of electrical switch & relay problems on a 2021 Audi A8?
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 Audi A8 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 Audi A8?
First match the engine — each row shows which engine(s) the part fits. 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 Audi A8
Electrical Switch & Relay Parts for Other Audi A8 Years
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