This page lists 13 electrical bulb & socket parts for the 2021 Audi A4, across 6 part types, covering both the 2.0L L4 ELECTRIC/GAS Turbocharged and the 2.0L L4 Turbocharged. Every part shows its brand, manufacturer part number and fitment notes.
On the 2021 Audi A4, the bulb and socket system covers every bulb and socket on the vehicle, from headlamps to instrument-cluster illumination. Most of the listed parts are Headlamp Bulb (4 parts), Glove Box Light Bulb (3 parts) and Turn Signal Lamp Bulb (3 parts). The other 3 part types cover the remaining 3 parts.
The 2021 Audi A4 was sold with both the 2.0L L4 ELECTRIC/GAS Turbocharged and the 2.0L L4 Turbocharged. Every part on this page is engine-specific. Each part shows which engine(s) it fits.
The most listed brands for 2021 Audi A4 electrical bulb & socket parts are PHILIPS (7 parts), SYLVANIA (4 parts) and ÜRO PARTS (1 part), plus 1 more brand. Quality grades include Standard Replacement, HID and Extended Life.
Each part number listed for the 2021 Audi A4 opens a page with every vehicle that part fits.
Brake Light Bulb
| Brand | Part Number | Markets | Notes | Buy |
|---|---|---|---|---|
| PHILIPS Fits: 2.0L L4 Turbocharged | 1156RLED | 🇺🇸 US 🇨🇦 CA 🇲🇽 MX | VisionLED | View on Amazon |
This table covers the bulbs in the stop lamps. Typical signs include a dark lamp, flicker, or a bulb that keeps failing in one socket. If the same position keeps failing, replace the socket or repair the ground rather than chasing bulbs.
One part is listed for the 2021 Audi A4 — PHILIPS 1156RLED.
Fog / Driving Lamp Bulb
| Brand | Part Number | Markets | Notes | Buy |
|---|---|---|---|---|
| PHILIPS Fits: 2.0L L4 Turbocharged | H21W | 🇺🇸 US 🇨🇦 CA 🇲🇽 MX | A4 Quattro | View on Amazon |
This table covers the bulbs in the fog and driving lamps. Typical signs include a dark lamp, flicker, or a bulb that keeps failing in one socket. If the same position keeps failing, replace the socket or repair the ground rather than chasing bulbs.
This group shows a single part: PHILIPS H21W.
Glove Box Light Bulb
Extended Life
| Brand | Part Number | Markets | Notes | Buy |
|---|---|---|---|---|
| SYLVANIA Fits: 2.0L L4 Turbocharged | 2821LL | 🇺🇸 US 🇨🇦 CA 🇲🇽 MX | Long LifeBase Type: W2.1x9.5d | View on Amazon |
Standard Replacement
| Brand | Part Number | Markets | Notes | Buy |
|---|---|---|---|---|
| PHILIPS Fits: 2.0L L4 Turbocharged | 12256 | 🇺🇸 US 🇨🇦 CA 🇲🇽 MX | A4 Quattro | View on Amazon |
| SYLVANIA Fits: 2.0L L4 Turbocharged | 2821 | 🇺🇸 US 🇨🇦 CA 🇲🇽 MX | A4 Quattro | View on Amazon |
This table covers the bulbs in the glove-box lamp. Typical signs include a dark lamp, flicker, or a bulb that keeps failing in one socket. If the same position keeps failing, replace the socket or repair the ground rather than chasing bulbs.
3 Glove Box Light Bulb parts for the 2021 Audi A4 come from 2 brands — SYLVANIA and PHILIPS.
In the Extended Life grade, SYLVANIA supplies 1 part: grouped under the catalog's "Extended Life" designation — the notes column spells out what sets them apart. A representative part number is SYLVANIA 2821LL.
In the Standard Replacement grade, PHILIPS and SYLVANIA supply 2 parts: built to original-equipment specification. A representative part number is PHILIPS 12256.
This group includes SYLVANIA 2821LL, PHILIPS 12256 and SYLVANIA 2821.
Headlamp Bulb
HID (intense white light)
| Brand | Part Number | Markets | Notes | Buy |
|---|---|---|---|---|
| SYLVANIA Fits: 2.0L L4 Turbocharged | D5S | 🇺🇸 US 🇨🇦 CA 🇲🇽 MX | High Beam and Low BeamA4 Quattro | View on Amazon |
| ÜRO PARTS Fits: 2.0L L4 Turbocharged | D5S | 🇺🇸 US 🇨🇦 CA 🇲🇽 MX | A4 QuattroXenon (12V - 25W) | View on Amazon |
| WAGNER Fits: 2.0L L4 Turbocharged | D5S | 🇺🇸 US 🇨🇦 CA 🇲🇽 MX | High Beam and Low BeamA4 Quattro | View on Amazon |
Standard Replacement
| Brand | Part Number | Markets | Notes | Buy |
|---|---|---|---|---|
| PHILIPS Fits: 2.0L L4 Turbocharged | H8 | 🇺🇸 US 🇨🇦 CA 🇲🇽 MX | High BeamA4 Quattro | View on Amazon |
This table covers the bulbs that light the headlamps. Typical signs include a dark lamp, a flicker over bumps, or a bulb that keeps failing on one side. Avoid touching a halogen capsule. Repeated failure in one socket is usually the socket or ground, not the bulb.
4 Headlamp Bulb parts for the 2021 Audi A4 come from 4 brands — SYLVANIA, ÜRO PARTS, WAGNER and 1 other brand.
In the HID (intense white light) grade, SYLVANIA, ÜRO PARTS and WAGNER supply 3 parts: grouped under the catalog's "HID (intense white light)" designation — the notes column spells out what sets them apart. A representative part number is SYLVANIA D5S.
Standard Replacement: 1 part, from PHILIPS. A representative part number is PHILIPS H8.
Listed part numbers: SYLVANIA D5S, plus the other parts above.
Tail Lamp Bulb
| Brand | Part Number | Markets | Notes | Buy |
|---|---|---|---|---|
| PHILIPS Fits: 2.0L L4 Turbocharged | 1156RLED | 🇺🇸 US 🇨🇦 CA 🇲🇽 MX | VisionLED | View on Amazon |
This table covers the bulbs in the tail lamps. Typical signs include a dark lamp, flicker, or a bulb that keeps failing in one socket. If the same position keeps failing, replace the socket or repair the ground rather than chasing bulbs.
This group shows a single part: PHILIPS 1156RLED.
Turn Signal Lamp Bulb
Extended Life
| Brand | Part Number | Markets | Notes | Buy |
|---|---|---|---|---|
| PHILIPS Fits: 2.0L L4 Turbocharged | PY21WLL | 🇺🇸 US 🇨🇦 CA 🇲🇽 MX | Longer LifeNatural Amber | View on Amazon |
Standard Replacement
| Brand | Part Number | Markets | Notes | Buy |
|---|---|---|---|---|
| PHILIPS Fits: 2.0L L4 Turbocharged | 12174NA | 🇺🇸 US 🇨🇦 CA 🇲🇽 MX | Natural Amber | View on Amazon |
| Brand | Part Number | Markets | Notes | Buy |
|---|---|---|---|---|
| SYLVANIA Fits: 2.0L L4 Turbocharged | PWY24W | 🇺🇸 US 🇨🇦 CA 🇲🇽 MX | FrontA4 Quattro | View on Amazon |
This table covers the bulbs in the turn-signal lamps. Typical signs include a dark lamp, flicker, or a bulb that keeps failing in one socket. If the same position keeps failing, replace the socket or repair the ground rather than chasing bulbs.
3 Turn Signal Lamp Bulb parts are listed for the 2021 Audi A4, from PHILIPS and SYLVANIA.
The Extended Life section: 1 option from PHILIPS. PHILIPS PY21WLL is listed in this group.
The Standard Replacement section: 1 option from PHILIPS. PHILIPS 12174NA is listed in this group.
1 ungrouped part is not assigned to a grade, with the same engine-level match.
Listed part numbers: PHILIPS PY21WLL, PHILIPS 12174NA and SYLVANIA PWY24W.
Buying Electrical Bulb & Socket Parts for a 2021 Audi A4
On this vehicle, the bulb and socket system covers every bulb and socket on the vehicle, from headlamps to instrument-cluster illumination.
- Match the engine first. Every electrical bulb & socket part here is 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, replace bulbs in pairs so both sides age together, and put a smear of dielectric grease on the new socket contacts.
- Cross-reference the manufacturer part number against your old part or a service-manual listing.
Start with the largest groups on this page: Headlamp Bulb and Glove Box Light Bulb .
Frequently Asked Questions
How many electrical bulb & socket parts fit the 2021 Audi A4?
Our catalog currently lists 13 electrical bulb & socket parts for the 2021 Audi A4 across 6 subcategories and 4 brands, covering both the 2.0L L4 ELECTRIC/GAS Turbocharged and the 2.0L L4 Turbocharged. Each part is matched to the engine(s) it fits.
Do electrical bulb & socket parts differ between 2021 Audi A4 engines?
Yes. Every electrical bulb & socket part on this page is engine-specific. Each row shows which engine(s) it fits — use the filter at the top to hide the rest. 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 bulb & socket problems on a 2021 Audi A4?
Common symptoms include a lamp that flickers over bumps, melted or discolored socket plastic, or bulbs that keep failing early on one side. 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, replace bulbs in pairs so both sides age together, and put a smear of dielectric grease on the new socket contacts.
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 A4 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 A4?
First match the engine — each row shows which engine(s) the part fits. Then repeated bulb failure in one position usually means a socket or ground problem, not bad bulbs — replace the socket rather than chase it. The notes column carries position and trim qualifiers where they apply.
Other Parts for the 2021 Audi A4
Electrical Bulb & Socket Parts for Other Audi A4 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.