Buy Mercedes-Benz S500 Tail Light Assembly

Overview

The Mercedes-Benz S500 tail light-also called the rear lamp, tail lamp, or brake light-is the red safety light at the back of the big luxury sedan. It lets drivers behind you see the car at night, shows when you brake, and flashes when you signal a turn. Over five vehicle generations, the S-Class moved from simple bulbs to smart LED and even OLED patterns, yet the core job stayed the same: bright, clear, legal light that keeps you-and everyone else-safe on the road. (NHTSA)

Tail-Light Basics

Mercedes groups several lights into one rear-combination assembly:

• Parking / tail lamp - steady red glow so others can see you. (NHTSA)
• Stop lamp (brake lamp) - gets brighter red when you press the pedal. (NHTSA)
• Turn-signal lamp - flashes amber or red to show turns or lane changes. (NHTSA)
• Reverse lamp - white light that helps you back up safely. (mercedesmedic.com)
• Rear reflector - passive red piece that still shows the car when the bulbs are off. (NHTSA)

Model-Year Changes

• W220 (1999-2006) - Uses twin-filament P21/5W bulbs for running-light and brake duties; amber PY21W bulbs for turns. (AutohausAZ)
• W221 (2007-2013) - Early cars mix bulbs and LEDs; 2010 facelift swaps to full LED arrays and adds a self-check warning for failed diodes. (MBWorld)
• W222 (2014-2020) - Standard full-LED "torch" pattern; sequential indicator on European cars. (NHTSA)
• W223 (2021-present) - Slim "digital skyline" LEDs with software-controlled animations; same part family across S500, S580, Maybach. (Kunzmann)

Key Components

• Lens: molded red or clear plastic with color filters.
• Housing: holds circuit board, seals, and gasket.
• Printed-circuit board (PCB): routes power to each LED or bulb.
• Gasket & vent: keeps out water but lets heat escape.
• Connector: 8- to 12-pin plug that feeds power and CAN-bus signals. (AutoProtoWay)

Materials & Build

Tail-light lenses are almost always polycarbonate (PC) because PC is tough, clear, and resists UV damage, yet weighs far less than glass. (Fabrik Molded Plastics, Wikipedia)
Many housings use reinforced polypropylene (PP) for heat stability, while seals rely on EPDM rubber. Modern Mercedes LEDs sit on aluminum heat sinks to pull away warmth and extend life. (Plastic Mold)

Legal & Safety Rules

In the U.S. the lamp must meet Federal Motor Vehicle Safety Standard 108:

• Color: red for tail/stop, amber or red for turn, white for reverse. (NHTSA)
• Brightness: tail lamp ≥ 2 cd; stop lamp ≥ 80 cd. (NHTSA)
• Location: as far apart as practical and at the same height left-to-right. (NHTSA)
• Flash rate: 60-120 blinks per minute for indicators. (NHTSA)

Mercedes tail lights also carry "E-mark" codes to satisfy UN ECE rules in other regions.

Common Issues

← scroll table horizontally →

Maintenance Tips

• Clean lenses with mild soap; avoid harsh solvents that cloud PC plastic.
• Seal checks: replace gasket if you see water droplets inside.
• Bulb care: on W220 change both left and right P21/5W at the same time to keep brightness even. (AutohausAZ)
• Connection care: add a dab of dielectric grease on the multi-pin plug during re-install to fight future corrosion. (The Drive)

Replacement Steps (DIY)

1. Open trunk and remove trim panel over the tail-lamp nuts.
2. Unplug connector-press locking tab and pull straight back.
3. Undo four 8 mm nuts holding the lamp; hand-tight only at 5 N·m when reinstalling. (YouTube)
4. Slide lamp outward; avoid scratching paint.
5. Swap bulbs or fit new assembly, then reverse steps.
6. Test lights and clear any dash warnings with OBD scan.

Diagnostics & Electronics

The rear Signal Acquisition Module (SAM) is the "smart fuse box" that powers and monitors every rear lamp. A bad SAM can keep LEDs dark, throw false warnings, or drain the battery. Use a scan tool to read codes like B1048 (short to B+). (mercedesmedic.com)

Upgrade Options

• LED retrofit kits for early W220 models give brighter light and use less power (check local laws).
• Sequential turn modules add flowing amber signals to W221 housings. (YouTube)
• Tint films offer smoked or clear-red looks; stay within 70 % minimum light transmission rules.
• Coding tweaks (with Xentry or similar) can enable European "rear fog" on U.S. cars. Consult a qualified technician first.

Frequently Asked Questions

Q: What bulb size fits a 2004 S500 tail lamp?
A: The outer brake/running bulb is a dual-filament P21/5W (7528). (AutohausAZ)

Q: Why does my dash show "Tail Lamp Left" even after I changed the bulb?
A: Corroded contacts in the bulb carrier can raise resistance; clean or replace the carrier to clear the fault. (The Drive)

Q: What does SAM stand for?
A: Signal Acquisition Module-an electronic relay box that powers, monitors, and reports on lights and many other rear functions.

Q: Can I swap a used tail-light assembly from an S580 into my S500?
A: Yes, on the same W223 chassis. Make sure the part number (e.g., A223 906 2300) matches the side and connector style. (Kunzmann)

Q: Are the new S-Class lights OLED?
A: They are high-density LED, not true organic OLED, but they do create thin, even light shapes similar to OLED panels. (NHTSA)

Q: Is extra coding needed after installing a new lamp?
A: On W222/W223 the SAM usually self-learns, but a dealer can perform "teach-in" coding if the warning stays. (Diagnostic Network)

Q: How bright must my tail lamp be to pass inspection?
A: U.S. law requires at least 2 candela for the running light and 80 candela for the stop light. (NHTSA)

Q: What material is the red lens made from?
A: Impact-resistant polycarbonate with a UV-hard-coat to stop yellowing. (Fabrik Molded Plastics, AutoProtoWay)

Q: Will tinting the lens make it illegal?
A: If tint cuts light below the FMVSS minimum you can fail safety inspection-check local rules before applying film. (NHTSA)

Q: My left rear light stays on even with the key out-what now?
A: Scan the rear SAM for stuck-relay faults. A water-damaged SAM can feed power continuously to the lamp. (Diagnostic Network)