2021 Audi A5 Electrical Switch & Relay Parts

Engine:
2.0L L4 Turbocharged

The 2021 Audi A5 has 23 electrical switch & relay parts with verified fitment on this page — 13 part types and 9 brands, covering the 2.0L L4 Turbocharged engine. Each part includes a manufacturer part number and application notes.

The switch and relay system on the 2021 Audi A5 covers the switches, relays and flashers that route power to everything the driver touches. The largest groups are Oil Pressure Sender / Switch (7 parts), A/C Refrigerant Pressure Switch (3 parts) and Brake Light Switch (2 parts). The other 10 part types cover the remaining 11 parts.

A/C Condenser Fan Motor Relay

Brand Part Number Markets Notes Buy
HELLA 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.

A/C Refrigerant Pressure Switch

Brand Part Number Markets Notes Buy
FOUR SEASONS 37427
🇺🇸 US 🇨🇦 CA 🇲🇽 MX
Pressure Switch
Fitment notes — FOUR SEASONS 37427
Pressure Switch
Transducer
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Amazon
UAC SW11103C
🇺🇸 US 🇨🇦 CA
Pressure Transducer
Fitment notes — UAC SW11103C
Pressure Transducer
Fits:
A5 SportbackKomfortTransduceror A5 SportbackPremiumDITransduceror PremiumMFITransducer
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Amazon
UAC SW11224C
🇺🇸 US 🇨🇦 CA 🇲🇽 MX
Pressure Transducer
Fitment notes — UAC SW11224C
Pressure Transducer
Fits:
A5 QuattroTransduceror A5 SportbackPremium PlusDITransduceror A5 SportbackPrestigeDITransduceror A5 SportbackProgressiv or TechnikTransduceror Mild Hybrid EV-Gas (MHEV)A5 SportbackTransduceror Premium PlusMFITransduceror PrestigeMFITransducer
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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.

Accessory Power Relay

Brand Part Number Markets Notes Buy
HELLA 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.

Brake Light Switch

Economy

Brand Part Number Markets Notes Buy
ÜRO PARTS 5G0698459
🇺🇸 US 🇨🇦 CA 🇲🇽 MX
A5 Sportback
View on
Amazon

Standard Replacement

Brand Part Number Markets Notes Buy
WELLS 1S10862
🇺🇸 US 🇨🇦 CA 🇲🇽 MX
A5 Quattro or A5 Sportback
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.

Fog / Driving Lamp Relay

Brand Part Number Markets Notes Buy
HELLA 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.

Fuel Pump / Circuit Opening Relay

Brand Part Number Markets Notes Buy
HELLA 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.

Horn Relay

Brand Part Number Markets Notes Buy
WELLS 1R2303
🇺🇸 US 🇨🇦 CA 🇲🇽 MX
Mounting Hardware Included: No
Fitment notes — WELLS 1R2303
Mounting Hardware Included: No
A5 Quattro or A5 Sportback
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.

Multi-Function Relay

Brand Part Number Markets Notes Buy
ÜRO PARTS 7M0951253A
🇺🇸 US 🇨🇦 CA 🇲🇽 MX
A5 Quattro or A5 Sportback
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Amazon
WELLS 1R1007
🇺🇸 US 🇨🇦 CA 🇲🇽 MX
Mounting Hardware Included: No
Fitment notes — WELLS 1R1007
Mounting Hardware Included: No
A5 Quattro or A5 Sportback
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.

Oil Pressure Sender / Switch

Economy

Brand Part Number Markets Notes Buy
REIN Popular ELP0078
🇺🇸 US 🇨🇦 CA 🇲🇽 MX
A5 Quattro or A5 SportbackBrown, with .55-.85 Bar
View on
Amazon
WALKER PRODUCTS 2561102
🇺🇸 US 🇨🇦 CA 🇲🇽 MX
A5 Quattro or A5 Sportback
View on
Amazon

Standard Replacement

Brand Part Number Markets Notes Buy
HELLA Popular 009600281
🇺🇸 US
1-Pin ConnectorHousing Color: Green
View on
Amazon
STANDARD MOTOR PRODUCTS PS665
🇺🇸 US 🇨🇦 CA 🇲🇽 MX
BlackColor: Green
Fitment notes — STANDARD MOTOR PRODUCTS PS665
BlackColor: Green
Fits:
A5 Base Modelwith LightGreenwith 1 Blade Terminalsor A5 Sportbackwith Gauge
View on
Amazon
VEMO V10720420
🇺🇸 US 🇨🇦 CA 🇲🇽 MX
From 08/28/2017To 07/31/2023
View on
Amazon
WELLS 1S16087
🇺🇸 US 🇨🇦 CA 🇲🇽 MX
A5 Quattro or A5 Sportback0.3 - 0.6 Bar
Fitment notes — WELLS 1S16087
A5 Quattro or A5 Sportback0.3 - 0.6 Barwith 1 PinsGreen
View on
Amazon
Brand Part Number Markets Notes Buy
WELLS 1S17518
🇺🇸 US 🇨🇦 CA 🇲🇽 MX
A5 Quattro or A5 Sportback0.55 - 0.85 Bar
Fitment notes — WELLS 1S17518
A5 Quattro or A5 Sportback0.55 - 0.85 Barwith 1 Terminal(s)Brown
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.

Power Window Switch

Brand Part Number Markets Notes Buy
VEMO V10730721
🇺🇸 US
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.

Radiator Fan Relay

Brand Part Number Markets Notes Buy
HELLA 933332451
🇺🇸 US 🇨🇦 CA 🇲🇽 MX
4-pin connector
Fitment notes — HELLA 933332451
4-pin connector
Motor Relay
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.

Trunk Lid / Tailgate Release Switch

Brand Part Number Markets Notes Buy
VEMO V10730458
🇺🇸 US 🇨🇦 CA 🇲🇽 MX
Fits CoupeA5 Quattroor A5 Sportback
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.

Turn Signal Switch

Brand Part Number Markets Notes Buy
VEMO V10800003
🇺🇸 US 🇨🇦 CA 🇲🇽 MX
A5 Quattro or A5 Sportback
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.

Buying Electrical Switch & Relay Parts for a 2021 Audi A5

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 2.0L L4 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 Audi A5?

Our catalog currently lists 23 electrical switch & relay parts for the 2021 Audi A5 across 13 subcategories and 9 brands, covering the 2.0L L4 Turbocharged engine. Each part is matched to the engine(s) it fits.

What are the signs of electrical switch & relay problems on a 2021 Audi A5?

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 A5 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 A5?

Every part on this page is matched to the 2.0L L4 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 Audi A5

Electrical Switch & Relay Parts for Other Audi A5 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.