Buy Mercedes-Benz S550 Tail Light Assembly

Overview

The Mercedes-Benz S550 tail light-also called the rear tail lamp, stop-light assembly, or back-light housing-sits at the outer corners of the trunk lid and quarter panel. It holds the red running lights, brighter brake lights, amber turn signals, white reverse lights, and built-in reflectors. From the 2007-2013 W221 sedan to the 2014-2020 W222 models, every S-Class tail light switched to full LED technology, which lights up quicker than old bulbs and lasts longer (Wikipedia). LEDs can illuminate about 0.2 seconds sooner than incandescent bulbs, giving the driver behind roughly one extra car length to react at highway speed (Chem Connections).

Compatibility & Fitment

• W221 (2007-2013) sedans share the same outer housing but facelift (2010+) units have a different LED pattern; they plug-in but need coding if retro-fitted .
• W222 (2014-2017) pre-face lights are unique to this range (Wikipedia).
• W222 (2018-2020) facelift lights add a "stardust" OLED-style welcome animation; they will not fit earlier years without changing trunk trim and wiring .
• Coupé (C217) and Cabriolet (A217) tail lamps look similar but differ in shape and connector pins.
  Always match the model year, body style, and side (left/right) when ordering a replacement.

Design & Technology

LED chips sit on circuit boards inside a weather-sealed plastic lens. Because LEDs reach full brightness almost instantly, studies show average reaction-time gains of 170-300 ms compared with bulbs (ResearchGate), improving rear-end-crash safety. U.S. cars must meet Federal Motor Vehicle Safety Standard 108 for color, brightness, and location (eCFR), while Europe follows ECE R48 and ECE R7 rules for red tail lights and amber indicators (TRALERT®). The SAE J585 standard sets lab test methods for durability, vibration, and water resistance (SAE International).

Safety & Regulations

• FMVSS 108 requires tail lamps to be red and visible from 1,000 ft at night (eCFR).
• ECE R48 limits mounting height (250-1,500 mm) and spacing from the car edge (TRALERT®).
• SAE and UNECE rules demand a "tell-tale" on the dash if the rear lamp fails .
  Failing to meet these rules can cause a recall; owners can check open campaigns with their VIN at Mercedes-Benz USA's recall portal (Mercedes-Benz USA).

Common Issues

1. Condensation / water drops-A worn foam gasket or micro-crack lets moist air in, fogging the lens (Reddit).
2. LED segment outage-If several LEDs go dark, the internal driver board usually failed.
3. Cracked lens-Harsh sun or a tap in a parking lot can spider-crack the polycarbonate.
4. Power loss-Check fuse block in the right-rear trunk; S550 shows fuse 58R for rear lighting (YouTube).
5. Moisture after car-wash-Low-heat "bake" and silica-gel packs can dry the housing (YouTube).

Installation Steps

(Example for W222 sedan-process is similar on W221)

1. Open trunk and remove side-wall felt. A plastic clip tool helps.
2. Unplug the 6-pin wiring harness.
3. Undo four 10-mm nuts; support the lamp so it doesn't drop (YouTube).
4. Wiggle the tail light straight back; do not twist.
5. Clean the body gasket surface.
6. Seat the new lamp, torque nuts to about 6 Nm, and reconnect.
7. Test parking, brake, turn, and reverse functions before closing trim.

Maintenance Tips

• Wash lenses with pH-neutral soap; avoid abrasive pads that dull the clear coat.
• Wax the lens twice a year to block UV fade.
• Replace cracked gaskets early to stop fogging.
• After heavy rain, inspect the trunk cavity for drips under the lamp pocket.

Upgrades & Customization

Enthusiasts sometimes retrofit the facelift "crystal" or OLED-look assemblies for a modern appearance . Others add sequential turn modules or light-smoke tint films (note: some states restrict dark tints-check FMVSS 108) (eCFR). Car and Driver noted that Mercedes' refreshed light signature adds visual width and brand identity to the S-Class rear end .

Cost & Warranty

New LED tail lamp assemblies usually range from $450-$1,000 per side, depending on year and trim. Genuine lamps carry a limited parts warranty, often 12 months/unlimited miles. Labor at a dealer runs 0.5-1.0 hr. Using a VIN to order ensures correct wiring options such as night-view assist or adaptive rear signaling.

Frequently Asked Questions

Q: What bulbs do the S550 tail lights use?
A: All S550 tail lights from 2007 onward use sealed LEDs; there are no replaceable bulbs.

Q: Why did my left rear light get water inside?
A: The foam seal may have shrunk or cracked, letting humid air in. Replace the seal or the whole lamp if the vent is blocked (Reddit).

Q: Can I drive if one LED bar is out?
A: It is legal-risk; FMVSS 108 requires both sides to work. Replace the assembly soon (eCFR).

Q: Are 2018 OLED lights plug-and-play on a 2015 S550?
A: No. The facelift housing shape, wiring, and control module differ .

Q: How fast do LEDs light up compared with old bulbs?
A: Tests show up to 0.3 seconds faster, giving an extra 19 ft of stopping room at 65 mph (Chem Connections).

Q: Is there a fuse for the tail lamp?
A: Yes-fuse 58R (right) and 59L (left) in the trunk fuse block protect the circuits (YouTube).

Q: My dash shows "Tail Lamp Out" but all LEDs work. Why?
A: Moisture or a failing rear SAM control module can trigger false errors .

Q: Do I need to re-code the car after replacing a lamp?
A: On W221 models upgrading to facelift LEDs, coding is required; on same-year replacements, no coding is needed .

Q: What torque for the mounting nuts?
A: About 6 Newton-meters (53 inch-pounds) keeps the lamp snug without cracking the studs (YouTube).

Q: Are smoked tail-light films legal?
A: Many states ban tints that reduce red light intensity below FMVSS 108 minimum; check local law first (eCFR).

Q: How can I dry fogged lights at home?
A: Remove the lamp, open the bulb-access cap, and blow warm air through, or set it in a warm, dry room with silica packs overnight (YouTube).

Q: Will a recall fix my cracked lens?
A: Recalls only cover safety defects announced by Mercedes; enter your VIN on their recall site to confirm (Mercedes-Benz USA).

Q: Does the S550 tail lamp have a built-in resistor for rapid flash?
A: The LED module includes its own load resistors; no external load is needed.

Q: Can I replace just the clear outer lens?
A: No. The lens is heat-welded to the housing; you must replace the complete tail-light unit.

Q: Are tail lamps side-specific?
A: Yes-the left and right assemblies mirror each other and have different part numbers.

References

1. 49 CFR 571.108 FMVSS 108  (eCFR)
2. SAE J585 Tail Lamp Standard  (SAE International)
3. Avago Application Note 1155-3 (UMTRI LED study)  (Chem Connections)
4. IEEE Access Brake-Light Reaction-Time Study 2021  (ResearchGate)
5. Mercedes-Benz USA Recall Lookup  (Mercedes-Benz USA)
6. Wikipedia-Mercedes-Benz W222 S-Class  (Wikipedia)
7. Mercedes OLED Tail-Lamp Preview (YouTube) 
8. W222 S550 Tail-Lamp Removal Guide (YouTube)  (YouTube)
9. Fuse-Box Location Video (YouTube)  (YouTube)
10. Owner Discussion on Condensation (Reddit)  (Reddit)
11. DIY Moisture Removal Video (YouTube)  (YouTube)
12. TRALERT® Guide to ECE R48 Lighting Rules  (TRALERT®)
13. HELLA Legal Lighting Requirements PDF 
14. MBWorld W221 Tail-Lamp Install Thread 
15. Car and Driver 2018 S63 Review (light design)