Taillight W166 for Mercedes-Benz GLS-CLASS

OE spec tail light, rear lamp assembly, engineered for the Mercedes Benz GLS Class X166, often listed alongside W166 parts in some catalogs. Restores factory lighting, visibility and safety after damage, fading or LED failure. Sold per piece, select Left or Right, and Outer quarter panel or Inner tailgate.

What this is / isn’t:
Included: 1× tail light assembly, position specific.

Important: Match facelift vs pre facelift, GL X166 vs GLS X166 styling, LED vs bulb type, AMG Line or Night Package trims. Outer and inner lamps are different parts, some versions require coding or a matching control unit. Always confirm by VIN or OE number.

Key Features:

• Exact fitment: Factory mounting points, lens contours and connector type for a no mod install.

• OEM grade optics: Correct reflector geometry and light distribution for legal road use.

• Sealed housing: Quality gaskets resist moisture ingress and lens haze.

• Uniform illumination: LED variants provide consistent brake and tail intensity.

• Durable lens: UV stable polycarbonate resists yellowing and cracking.

Compatibility:

• GLS Class X166, approx. 2016 to 2019, verify by VIN.

• May cross with late GL Class X166, 2012 to 2015, where specified, styling differs by facelift.

• Works on 4MATIC and 2WD where applicable, market spec and trim can change the part.

Options, lamp positions and types:

• Outer tail lamp, quarter panel → select Left or Right Outer.

• Inner tail lamp, tailgate → select Left or Right Inner.

• Lighting type → LED integrated or bulb type with separate holder, match your existing system.

• Facelift, GLS rename → updated light signature may require matching inner and outer pairs.

Typical OE reference families, guide only:
A166 906 …, A166 907 …, outer or inner variations by year and market.
Always order by the exact OE part number on your vehicle or confirm via VIN.

When to replace a tail light:

• Cracked or broken lens after impact.

• LED strip failure, partial illumination or flicker.

• Persistent moisture or condensation inside the housing.

• Fault codes for lamp circuit or dim output.

Installation notes, pro tips:

• Identify position, Left or Right, Inner or Outer, and facelift status before ordering.

• Disconnect battery, handle connectors gently, avoid twisting the seal.

• Transfer bulb holders or control units if your version requires it.

• Test all functions, tail, brake, indicator, reverse, fog, before refitting trims.

• Some LED versions may need coding or adaptation to clear warnings.

What’s included / not included:
✅ 1× Tail light assembly, choose Left or Right, Inner or Outer
❌ Bulb holder if separate, LED control unit if separate, wiring, brackets, hardware or clips

Q&A
Q1: Will this fit both GL X166 and GLS X166?
Often yes where specified, but designs differ around the facelift rename. Match by VIN or OE to be sure.
Q2: Do I need coding after replacement?
Bulb type usually not, many LED versions may require coding or adaptation to clear errors.
Q3: Are inner and outer lamps interchangeable?
No, inner tailgate and outer quarter panel lamps are different shapes and connectors.
Q4: How do I confirm AMG Line?
AMG Line has different bumper and trim details. Check your build sheet for code P31 or match by VIN.

Why choose TOParts:
OE grade lighting for Mercedes Benz SUVs with precise fitment, correct optics and long term reliability, trusted by panel shops and independent Mercedes specialists across South Africa.