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Heated left mirror glass A1698102121 for Mercedes W169/W245: the practical guide

If the left mirror on your A-Class or B-Class stays fogged long after the windscreen has cleared, the heating grid in the glass has usually failed. The Left Rearview Mirror Glass Heated for Mercedes W169/W245 (A1698102121) is the direct replacement — same part number as the factory unit, same snap-fit carrier, same 2-pin heated connector.

It is a heated, non-dimming convex glass for the left side of LHD cars, built to 2026 ISO 16750-4 environmental endurance standards and passing the updated ECE R46 revision 5 curvature and reflectivity mandates. It fits the Mercedes-Benz W169 A-Class (2008–2012) and W245 B-Class (2008–2011). Unclip the old glass, unplug one connector, plug this one in, clip it home. No coding, no adapters.

Fitment: check your model, then your side

The A1698102121 covers the W169 A-Class A150/A170/A180/A200 (2008–2012) and the W245 B-Class B150/B170/B180/B200 (2008–2011). On left-hand-drive cars this is the driver-side mirror. The part sits in Mercedes EPC Group 72.220 and cross-references to OEM number 1698102121.

Right-hand-drive cars: read this twice

On an RHD W169 or W245, the left glass physically lands on the passenger side. For the driver-side (right) mirror on an RHD import you need A1698102221 instead. Curvature is side-specific — convex, typically a 1200R radius per ECE R46 — so mixing sides compromises the field-of-view safety envelope. SA code 500 in your vehicle's EPC datacard shows how yours was built.

If you service RHD imports, the same side logic runs through all door electrics. Koeep also stocks the Master Power Window Control Switch for the 2008–2014 Hyundai i20 hatchback RHD for that reason.

2026 compliance, in plain terms

• ECE R46 Rev.5 — locks curvature and ≥40% reflectivity, so your field of view matches the factory mirror.
• EU ELV Directive 2000/53/EC, 2026 amendment — lead-free soldered heating terminals and a recyclable glass substrate.
• REACH 2026 Annex XVII / SVHC Candidate List Rev. 35 — adhesive backing free of PVC, phthalates and PFAS, UL 94 HB rated.
• ISO 9227:2022 — the reflective layer survives ≥480 hours of neutral salt spray without pitting.
• IATF 16949:2016 production, PPAP Level 3 — documentation available for fleet operators and insurance repair networks.

Full specification table

How the glass is built

Substrate and coating

The base is borosilicate float glass, 1.8 mm thick with a ±0.05 mm tolerance. A chromium-aluminium reflective layer is applied by vacuum deposition and reaches at least 40% reflectivity. A nano-ceramic topcoat protects the outer face from grit and car-wash brushes.

Heating grid

The grid is screen-printed silver-palladium (Ag-Pd) conductive paste with 0.25 mm traces, sintered at 620°C so it fuses into the glass itself. That bond is why the part survives thermal cycling from −40°C to +90°C without delaminating, and why the alloy resists the corrosion and silver migration that kill older mirror grids.

Adhesive and connector

On the back, a closed-cell PE-X foam film with 3M™ 300LSE acrylic adhesive replaces older PU foam, adding 40% shear strength and resisting plasticizer migration from the carrier plate. The 2-pin terminals stay below 0.05 mΩ contact resistance after 10,000 mating cycles.

Diagnosing mirror heating faults

Codes worth scanning for

Use a scan tool that meets SAE J1979-2 and query the Left Door Control Module (DCM-L) over ISO 15765-4 CAN, 11-bit, 500 kbps. These codes tie into the heater circuit:

• B1C62-13 — heater circuit open. Broken grid trace or unplugged connector. Resistance above 1 MΩ means replace the glass.
• B1C62-11 — short to ground. Inspect the harness between A-pillar and door for chafing.
• U0198-87 — lost communication with Door Control Module A. Check SAM CAN-high/low bias at 2.5V ± 0.1V before blaming the glass.

Bench test before you install

Take a calibrated digital multimeter — a Fluke 87V or equivalent — set it to ohms and probe the two terminals on the back of the glass. A healthy unit reads 9.8–10.5 Ω at 20°C. Then apply 12V DC for 60 seconds: the whole surface should reach 35–45°C, evenly, within ±3°C.

When the heater never switches off

Mirror heating is triggered by the rear window defroster relay (K40/4) through the SAM module, with a 10–15 minute auto-off timer. If yours runs past that, work down this list:

1. DTC B1C62-12 — shorted relay in the SAM. The fix is a new SAM unit, part A1695450032.
2. Ambient temperature sensor B14 — bad readings can hold heating on. Verify via PID $05 in the engine ECU data stream.
3. Your own install — make sure the 2-pin connector is not bridged or cross-wired with the mirror adjustment motor circuit.

Early warning signs of grid failure

The TÜV 2026 inspection guideline (§4.7.2) lists the markers: brown or discolored grid lines from silver migration, a partial defog pattern where only intact traces clear, a delamination halo wider than 5 mm from the edge under UV light, or resistance drifting more than 15% from nominal. Any of these means it is time for the A1698102121 replacement glass — before the first frost, not after.

Installation and ordering

The glass is a snap-fit design, so there is no torque spec. Press it home until the carrier plate clips engage with less than 3 mm of lateral play, and work between +10°C and +35°C ambient so the adhesive bonds properly. Order of work: open the mirror housing, ease the old glass out, unplug the 2-pin connector, plug the new glass in, press until the clips click, then repeat the 60-second thermal test.

Genuine, aftermarket and where to browse

This SKU replaces Mercedes-Benz Genuine part A1698102121, now limited availability via the MB Classic Center. Aftermarket equivalents are VAN WEZEL 5212831, TYC 337-0027 and ALKAR 6823690. Service life is projected at 2026–2030 under Koeep's QMS 8D-2026 framework.

Heated mirror glass is not a Mercedes-only topic. If you also wrench on trucks, the Koeep guide to the driver side power heated tow mirror for 2000–2002 Chevy GMC covers the same fog-and-failure logic. Riders are covered too, with motorcycle rearview mirrors for the BMW S1000RR (2009–2018) and HP4 (2011–2015) in the same store.

Browse the full Body Parts catalog at Koeep for mirrors, panels and related exterior components.

Frequently asked questions