Mercedes-Benz A-Class 177 / CLA 118 Illuminated Front Air Vents Installation Guide

This guide describes replacement illuminated front air vents for the 2019–2024 Mercedes-Benz A-Class 177 and CLA 118 listed in the source. The parts illustration identifies W177, and the photographs show the illustrated installation rather than every CLA or interior variant. Confirm the vent shape, existing ambient-lighting system, controller and supplied harness for the vehicle before installation.

The source describes synchronization with ambient-lighting color changes, breathing mode and welcome mode. It does not establish that every function of a higher-specification vehicle is available on every retrofit configuration.

1. Parts and controller requirements

Figure 1 shows five front vents, a vent-lighting harness, an extension lead, a controller and a controller power/communication harness. Its reference numbers identify these parts:

The pictured controller label identifies a 2.4G main module (Tx). Its three output labels read lower dashboard light strip, air vents and upper dashboard light strip. These labels identify output uses on the pictured module; they do not establish connector pin assignments or require adding dashboard light strips to this vent installation. The numbers in the parts diagram are component references, not connector pins. The diagram does not supply a terminal map or module setting procedure.

The source distinguishes two installations: where ambient lighting has already been installed, the vents are connected to its ambient-lighting module; where no ambient lighting is installed, a controller is required to drive the front vents. This description does not confirm compatibility with every existing controller or other brand's system. Verify the controller and harness match for the actual installation.

2. Remove the existing vent assemblies and route the wiring

Follow the photographs from top to bottom:

1. Remove the two T20 screws indicated at the climate-control panel.
2. Use two small flat-blade screwdrivers to lift the hidden retaining clips shown at the central vent assembly. Then use the pictured trim-pry tool to remove the assembly.
3. Pull the left and right side vent assemblies out as shown.
4. The source marks the module location at the passenger-side lower A-pillar, near the front door.
5. In the configuration with the illustrated module and adapter, connect the module inline at connector No. 3 of the right-front door controller. The photograph shows the unused/reserved plug wrapped. “No. 3” is the illustrated connector reference, not terminal cavity 3.
6. Route the vent harness across the front dashboard to the five vent positions shown, with its module branch toward the passenger-side location.

The photographs identify placement and routing. They do not define supply voltage, fuse protection, a CAN-wire assignment, connector cavities or a vehicle electrical isolation procedure. Obtain the matching electrical instructions before connecting the harness.

3. Replace the vents and transfer the trim parts

1. Identify the replacement vents before fitting them. The source says the central vents are the same size; the side vents must be distinguished as left and right.
2. Remove the indicated T20 screws from the central vent carrier and remove the existing vents. The source does not specify a screw count or tightening torque for this carrier.
3. Release and remove the existing vent trim covers at the illustrated clips.
4. Separate the trim cover, remove the existing vent gasket/ring and transfer it to the new illuminated vent as shown.
5. Fit the trim cover onto the illuminated vent.
6. Check that the transferred gasket/ring and retaining clips are fully seated at the highlighted positions.

The source photographs show the transfer and seating checks. Confirm the fastening and refitting procedure for the specific carrier and dashboard before reassembly.

4. Troubleshooting and other-brand wire-color example

The following checks come from the source. They are checks to help identify a fault, rather than proof that a particular component must be replaced:

1. All ambient lights remain off after coding: the source recommends reconnecting the ambient-lighting module's power connector, then locking the vehicle and allowing ten minutes of sleep before observing the result. Use the matching electrical procedure and confirm the supply, connections and coding rather than treating this symptom alone as a failed module.
2. One vent shows the wrong color: check the lamp-lead assignment and test red, green and blue in single-color mode. The source attributes a missing color to the lamp head; confirm that diagnosis before replacing the head.
3. Lighting is dim: check whether the lamp head is loose or not fully seated, and whether the connector is fully engaged.
4. Brightness cannot be adjusted and returns to zero: the source recommends reconnecting the ambient-lighting power connector and allowing the locked vehicle to sleep.
5. Wire colors differ when the vents are used with another brand's ambient lighting: the source provides the example below. It identifies the CKCP yellow lead as positive and the red, green and blue leads by their lamp-color channels.

Figure 4 labels the two harness sides “ours” and “other supplier.” The color table is a source-specific comparison, not a universal standard or a connector pinout. The source does not identify the other supplier or give terminal numbering, current ratings or a complete repinning method. Confirm both harnesses by their actual functions and connector documentation before changing any connection; do not infer pin positions from the photograph or wire colors alone.

The source refers to troubleshooting after coding but gives no vehicle-specific coding selections or controller configuration procedure. Those details, electrical protection, left/right vent fitment and final installation checks remain to be verified for the exact vehicle and kit.