Evaluating Replacement Glass for the C118 CLA Rear Window
Before installing a replacement rear window on this four-door coupe, I inspect the glass surface for embedded antenna traces and verify the tint shade against the car's build. Mercedes-Benz equips the C118 body with two distinct glass variants: a standard light-tint pane (corresponding to original reference 118-670-02-00-64 or A1186700200) and a dark privacy AS3 tempered option (matching reference 118-670-04-00-64 or A1186700400). Both variations incorporate identical integrated defroster patterns, but matching the exact visual opacity to the surrounding rear quarter glass is critical before moving forward.
Because the back window incorporates multiple functions into a stationary unit, physical inspections must confirm that all factory-bonded connection tabs are present and undamaged. The coupe uses direct-printed conductor grids that service not only the electric defogger, but also the AM/FM reception, cellular signals, and keyless entry frequencies. Unlike the front windshield, this rear pane contains no camera brackets, rain sensor hardware, or wiper shaft cutouts, so my focus remains strictly on the glass edges and electrical terminals.
| Glass Specification | Standard Clear/Green Tint | Dark Privacy Glass |
|---|---|---|
| Factory Part Reference | 118-670-02-00-64 (A1186700200) | 118-670-04-00-64 (A1186700400) |
| Safety Marking | DOT AS2 Tempered | DOT AS3 Tempered |
| Integrated Circuits | Defroster, AM/FM, Keyless/Cell | Defroster, AM/FM, Keyless/Cell |
| Perimeter Style | Encapsulated moulding lip | Encapsulated moulding lip |
I verify that the replacement panel features the correct encapsulated perimeter moulding lip. Because this car does not rely on a separate pull-off exterior rubber trim, any defect, distortion, or tear in the glass unit's pre-bonded border will create wind noise or an uneven profile against the surrounding sheet metal.
Setting Clearances and Interior Connection Points
Proper positioning on this coupe depends on specific lower channel setting blocks. The bottom border of the glass meets the front shut line of the steel trunk lid with exceptionally narrow margins, leaving virtually no room for vertical drift. I confirm that the lower support blocks from the 177/118 platform hardware series are correctly seated so the glass matches the exact height of the rear decklid without contacting the painted edges when the trunk closes.
Along the upper perimeter, the glass must sit flush relative to the vehicle's roof panel, which varies depending on whether the car has a painted steel top or the trailing glass section of a panoramic sliding sunroof. While adjacent panoramic roof panes on these vehicles expand significantly under heat, the rear window must maintain an even gap across the top margin so that water sheds cleanly into the side drainage channels rather than pooling near the center high-mounted stop lamp (CHMSL).
Every aftermarket rear pane I install is backed by a one-year glass warranty, and I back my own workmanship on the car for as long as you own it. Before setting the glass permanently into the aperture, I inspect the solder joints on the electrical pigtails to ensure they line up perfectly with the internal harness behind the C-pillar trims and rear parcel shelf, preventing any strain on the antenna amplifier leads.
Post-Installation Electrical and Alignment Verifications
Once the rear glass is resting in its final position, I run systematic functional checks on all embedded networks:
- Keyless and Remote Range: Testing lock, unlock, and keyless entry response from outside the vehicle to confirm the rear antenna array operates at full strength.
- Broadcast Reception: Checking both AM and FM bands across weak and strong stations to ensure no signal degradation or static caused by interrupted grid soldering.
- Defroster Grid Continuity: Running a resistance check across the upper and lower bus bars to verify complete heating circuit continuity before powering the rear defogger relay.
- Decklid Clearance: Cycling the trunk lid to confirm the leading metal edge clears the lower encapsulated glass edge with uniform side-to-side spacing.
- Interior Trim Alignment: Ensuring the upper edge of the glass lines up cleanly with the third brake light housing situated underneath the rear headliner trim.
