This page lists 28 electrical bulb & socket parts for the 2018 Cadillac XTS, across 11 part types, covering both the 3.6L V6 and the 3.6L V6 Turbocharged. Every part shows its brand, manufacturer part number and fitment notes.
The bulb and socket system on the 2018 Cadillac XTS covers every bulb and socket on the vehicle, from headlamps to instrument-cluster illumination. The largest groups are Back Up / Reverse Lamp Bulb (8 parts), License Plate Lamp Bulb (6 parts) and Door Panel Light Bulb (2 parts). The other 8 part types cover the remaining 12 parts.
The 2018 Cadillac XTS was sold with both the 3.6L V6 and the 3.6L V6 Turbocharged. 27 parts fit every engine; the other 1 is engine-specific. Each part shows which engine(s) it fits.
The most listed brands for 2018 Cadillac XTS electrical bulb & socket parts are SYLVANIA (9 parts), HELLA (7 parts) and WAGNER (6 parts), plus 3 more brands. Quality grades include Standard Replacement, Extended Life and Extra Bright.
4 parts on this 2018 Cadillac XTS page carry a "Popular" badge — the source catalog's flag for options frequently chosen for this vehicle — including SYLVANIA 921LL (Back Up / Reverse Lamp Bulb) and SYLVANIA 2825LL (License Plate Lamp Bulb). Click any part number to see every vehicle that part fits.
Back Up / Reverse Lamp Bulb
Extended Life
| Brand | Part Number | Markets | Notes | Buy |
|---|---|---|---|---|
| SYLVANIA Popular Fits: all 2018 XTS engines | 921LL | 🇺🇸 US 🇨🇦 CA | Long LifeBase Type: W2.1x9.2d | View on Amazon |
| WAGNER Fits: all 2018 XTS engines | 921LL | 🇺🇸 US 🇨🇦 CA | Long LifeWedge Base | View on Amazon |
Extra Bright (improved visibility, but shorter life)
| Brand | Part Number | Markets | Notes | Buy |
|---|---|---|---|---|
| SYLVANIA Fits: all 2018 XTS engines | 921ST | 🇺🇸 US 🇨🇦 CA | Cool WhiteSilver Star | View on Amazon |
LED (instant-on, long life, energy-saving)
| Brand | Part Number | Markets | Notes | Buy |
|---|---|---|---|---|
| WAGNER Fits: all 2018 XTS engines | 921WLED | 🇺🇸 US 🇨🇦 CA | LEDWhite | View on Amazon |
Standard Replacement
| Brand | Part Number | Markets | Notes | Buy |
|---|---|---|---|---|
| HELLA Popular Fits: all 2018 XTS engines | 921 | 🇺🇸 US 🇨🇦 CA | IncandescentSocket Type Bulb: W2.1x9.5d | View on Amazon |
| GM GENUINE Fits: all 2018 XTS engines | 13503360 | 🇺🇸 US 🇨🇦 CA | TRADE # W16WCLEAR | View on Amazon |
| SYLVANIA Fits: all 2018 XTS engines | 921 | 🇺🇸 US 🇨🇦 CA | Base Type: W2.1x9.2dWattage: 18.00 W | View on Amazon |
| WAGNER Fits: all 2018 XTS engines | 921 | 🇺🇸 US 🇨🇦 CA | Bulb Type: T-5 Bulb 5/8 (16mm) DiameterVoltage: 12.800 Volts (Direct Current) | View on Amazon |
This table covers the bulbs in the reverse 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.
8 Back Up / Reverse Lamp Bulb parts are listed for the 2018 Cadillac XTS, from SYLVANIA, WAGNER, HELLA and 1 other brand. SYLVANIA 921LL carries the "Popular" badge. All of them fit every engine offered in the 2018 XTS.
The Extended Life section lists 2 options from SYLVANIA and WAGNER — grouped under the catalog's "Extended Life" designation — the notes column spells out what sets them apart. SYLVANIA 921LL is listed in this group.
The Extra Bright (improved visibility, but shorter life) section lists 1 option from SYLVANIA — grouped under the catalog's "Extra Bright (improved visibility, but shorter life)" designation — the notes column spells out what sets them apart. SYLVANIA 921ST is listed in this group.
In the LED (instant-on, long life, energy-saving) grade, WAGNER supplies 1 part: grouped under the catalog's "LED (instant-on, long life, energy-saving)" designation — the notes column spells out what sets them apart. A representative part number is WAGNER 921WLED.
The Standard Replacement section lists 4 options from HELLA, GM GENUINE, SYLVANIA and 1 other brand — built to original-equipment specification. HELLA 921 is listed in this group.
Part numbers include SYLVANIA 921LL and SYLVANIA 921ST, among others listed above.
Dome Light Bulb
| Brand | Part Number | Markets | Notes | Buy |
|---|---|---|---|---|
| SYLVANIA Fits: all 2018 XTS engines | 2886XSL | 🇺🇸 US 🇨🇦 CA | LEDStraight Base Connector In Line with Bulb | View on Amazon |
This table covers the bulbs in the dome 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.
One part is listed for the 2018 Cadillac XTS — SYLVANIA 2886XSL.
Door Panel Light Bulb
| Brand | Part Number | Markets | Notes | Buy |
|---|---|---|---|---|
| HELLA Fits: all 2018 XTS engines | 2825 | 🇺🇸 US 🇨🇦 CA | IncandescentSocket Type Bulb: W2.1x9.5d | View on Amazon |
| HELLA Fits: all 2018 XTS engines | 2825BL | 🇺🇸 US 🇨🇦 CA | IncandescentSocket Type Bulb: W2.1x9.5d | View on Amazon |
This table covers the replacement bulbs for the Door Panel Light. 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.
2 Door Panel Light Bulb parts for the 2018 Cadillac XTS come from HELLA. Every part fits both the 3.6L V6 and the 3.6L V6 Turbocharged.
Part numbers include HELLA 2825 and HELLA 2825BL.
Headlamp Bulb
| Brand | Part Number | Markets | Notes | Buy |
|---|---|---|---|---|
| HELLA Fits: all 2018 XTS engines | D3S4300K | 🇺🇸 US 🇨🇦 CA | 4300KSocket Type Bulb: PK32D-5 | View on Amazon |
| WAGNER Fits: all 2018 XTS engines | D3S | 🇺🇸 US 🇨🇦 CA | with Xenon Gas | 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.
2 Headlamp Bulb parts for the 2018 Cadillac XTS come from 2 brands — HELLA and WAGNER. Every part fits both the 3.6L V6 and the 3.6L V6 Turbocharged.
Listed part numbers: HELLA D3S4300K and WAGNER D3S.
License Plate Lamp Bulb
Extended Life
| Brand | Part Number | Markets | Notes | Buy |
|---|---|---|---|---|
| SYLVANIA Popular Fits: all 2018 XTS engines | 2825LL | 🇺🇸 US 🇨🇦 CA | Long LifeBase Type: W2.1x9.5d | View on Amazon |
| WAGNER Fits: all 2018 XTS engines | 17177LL | 🇺🇸 US 🇨🇦 CA | Long LifeW2.1x9.5d Base | View on Amazon |
Extra Bright (improved visibility, but shorter life)
| Brand | Part Number | Markets | Notes | Buy |
|---|---|---|---|---|
| SYLVANIA Fits: all 2018 XTS engines | 2825ST | 🇺🇸 US 🇨🇦 CA | BlueSilver Star | View on Amazon |
LED (instant-on, long life, energy-saving)
| Brand | Part Number | Markets | Notes | Buy |
|---|---|---|---|---|
| SYLVANIA Fits: all 2018 XTS engines | 2825SL | 🇺🇸 US 🇨🇦 CA | LEDCool White | View on Amazon |
Standard Replacement
| Brand | Part Number | Markets | Notes | Buy |
|---|---|---|---|---|
| WAGNER Popular Fits: all 2018 XTS engines | 17177 | 🇺🇸 US 🇨🇦 CA | W2.1x9.5d Base5.000 Watt | View on Amazon |
| SYLVANIA Fits: all 2018 XTS engines | 2825 | 🇺🇸 US 🇨🇦 CA | Base Type: W2.1x9.5dWattage: 5.00 W | View on Amazon |
This table covers the bulbs that light the license plate. 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.
6 License Plate Lamp Bulb parts are listed for the 2018 Cadillac XTS, from SYLVANIA and WAGNER. SYLVANIA 2825LL carries the "Popular" badge. All of them fit every engine offered in the 2018 XTS.
The Extended Life section: 2 options from SYLVANIA and WAGNER. SYLVANIA 2825LL is listed in this group.
The Extra Bright (improved visibility, but shorter life) section: 1 option from SYLVANIA. SYLVANIA 2825ST is listed in this group.
LED (instant-on, long life, energy-saving): 1 part, from SYLVANIA. A representative part number is SYLVANIA 2825SL.
The Standard Replacement section: 2 options from WAGNER and SYLVANIA. WAGNER 17177 is listed in this group.
Listed part numbers: SYLVANIA 2825LL, WAGNER 17177LL and SYLVANIA 2825ST, plus the other parts above.
Parking Lamp Bulb
| Brand | Part Number | Markets | Notes | Buy |
|---|---|---|---|---|
| PHILIPS Fits: all 2018 XTS engines | 7444NALL | 🇺🇸 US 🇨🇦 CA | Longer LifeNatural Amber | View on Amazon |
This table covers the bulbs in the parking 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 7444NALL.
Side Marker Light Bulb
Extended Life
| Brand | Part Number | Markets | Notes | Buy |
|---|---|---|---|---|
| HELLA Fits: all 2018 XTS engines | 194LL | 🇺🇸 US 🇨🇦 CA | IncandescentLong Life | View on Amazon |
Standard Replacement
| Brand | Part Number | Markets | Notes | Buy |
|---|---|---|---|---|
| HELLA Fits: all 2018 XTS engines | 194 | 🇺🇸 US 🇨🇦 CA | Brightness: 2.0 CPIncandescent | View on Amazon |
This table covers the bulbs in the side-marker 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.
HELLA supplies both parts for the 2018 Cadillac XTS. All of them fit every engine offered in the 2018 XTS.
The Extended Life section: 1 option from HELLA. HELLA 194LL is listed in this group.
The Standard Replacement section: 1 option from HELLA. HELLA 194 is listed in this group.
Part numbers include HELLA 194LL and HELLA 194.
Step / Courtesy Light Bulb
| Brand | Part Number | Markets | Notes | Buy |
|---|---|---|---|---|
| GM GENUINE Fits: all 2018 XTS engines | 13500832 | 🇺🇸 US 🇨🇦 CA | RearCLEAR | View on Amazon |
This table covers the bulbs in the step and courtesy 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 2018 Cadillac XTS — GM GENUINE 13500832.
Tail Lamp Bulb
| Brand | Part Number | Markets | Notes | Buy |
|---|---|---|---|---|
| HELLA Fits: all 2018 XTS engines | 2825 | 🇺🇸 US 🇨🇦 CA | IncandescentSocket Type Bulb: W2.1x9.5d | 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: HELLA 2825.
Trunk / Cargo Area Light Bulb
| Brand | Part Number | Markets | Notes | Buy |
|---|---|---|---|---|
| PEAK Fits: 3.6L V6 | 168 | 🇺🇸 US 🇨🇦 CA | Trunk LightBulb | View on Amazon |
| SYLVANIA Fits: all 2018 XTS engines | 175SL | 🇺🇸 US 🇨🇦 CA | LED | View on Amazon |
This table covers the bulbs in the trunk or cargo-area 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.
2 Trunk / Cargo Area Light Bulb parts for the 2018 Cadillac XTS come from 2 brands — PEAK and SYLVANIA. 1 part fits every engine; the other 1 is engine-specific.
Listed part numbers: PEAK 168 and SYLVANIA 175SL.
Turn Signal Lamp Bulb
Extended Life
| Brand | Part Number | Markets | Notes | Buy |
|---|---|---|---|---|
| PHILIPS Fits: all 2018 XTS engines | 7444NALL | 🇺🇸 US 🇨🇦 CA | Longer LifeNatural Amber | View on Amazon |
Standard Replacement
| Brand | Part Number | Markets | Notes | Buy |
|---|---|---|---|---|
| GM GENUINE Fits: all 2018 XTS engines | 13503360 | 🇺🇸 US 🇨🇦 CA | Fits Platinum or Premium LuxuryTRADE # W16W | 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.
2 Turn Signal Lamp Bulb parts are listed for the 2018 Cadillac XTS, from PHILIPS and GM GENUINE. All of them fit every engine offered in the 2018 XTS.
The Extended Life section: 1 option from PHILIPS. PHILIPS 7444NALL is listed in this group.
The Standard Replacement section: 1 option from GM GENUINE. GM GENUINE 13503360 is listed in this group.
Listed part numbers: PHILIPS 7444NALL and GM GENUINE 13503360.
Buying Electrical Bulb & Socket Parts for a 2018 Cadillac XTS
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. Some electrical bulb & socket 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, 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: Back Up / Reverse Lamp Bulb and License Plate Lamp Bulb .
Frequently Asked Questions
How many electrical bulb & socket parts fit the 2018 Cadillac XTS?
Our catalog currently lists 28 electrical bulb & socket parts for the 2018 Cadillac XTS across 11 subcategories and 6 brands, covering both the 3.6L V6 and the 3.6L V6 Turbocharged. Each part is matched to the engine(s) it fits.
Do electrical bulb & socket parts differ between 2018 Cadillac XTS engines?
Some do. 27 parts fit every engine; the other 1 is 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 bulb & socket problems on a 2018 Cadillac XTS?
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 2018 Cadillac XTS 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 2018 Cadillac XTS?
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 2018 Cadillac XTS
Electrical Bulb & Socket Parts for Other Cadillac XTS Years
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