Table of Contents
Mercedes Dashboard Display Not Working? Causes, Diagnosis & Real Fix (MBUX / W177, W118, H247)
A blank or unresponsive dashboard display in your Mercedes-Benz A-Class W177, B-Class (W247), CLA W118, or GLA H247 can be alarming especially when the MBUX screen stays black even after starting the engine.
This issue is increasingly common in newer Mercedes models equipped with digital dashboards and dual-screen MBUX systems, where a software glitch, power supply fault, or damaged HVSL/SHD (LVDS) data cable can interrupt display communication.
When the driver’s screen fails to light up, or both screens remain dark with no welcome animation, it often indicates a disruption in power delivery, signal transmission, or module synchronization between the instrument cluster (IC213) and the head unit (HU6).
Understanding these causes and how to systematically diagnose them is essential before replacing any parts.
In this detailed case study, we’ll walk through the real-world diagnostic steps, workshop findings, and the final solution that restored full functionality to a Mercedes A-Class W177 with a black dashboard screen.
For a full overview of Mercedes screen, camera, and dashboard faults including black screens, flickering clusters, and 360° camera errors explore the main hub:
Mercedes Display and Camera Faults: Fix Dashboard, Screen Faults
Common Symptoms
- – Black, unresponsive instrument cluster or center screen
- – No welcome animation on door open
- – Intermittent flicker, ghosting, or delayed boot
- – Touch/controls work but no image
- – Works after restart then fails again (sporadic)
Symptom–Cause–Fix Table
| Symptom | Likely Cause | What to Check | Recommended Fix |
|---|---|---|---|
| Screen totally black | Weak/dead battery; blown fuse | Battery ≥12.4 V (OFF), fuses for IC/MBUX | Charge/replace battery; replace fuse |
| Black after door open + after start | MBUX/IC crash; outdated firmware | Quick Test (XENTRY), software levels | Soft reset; update/reflash IC/MBUX |
| Flicker / image cuts out on bumps | Loose/damaged HVSL/SHD (LVDS) | Inspect/ reseat LVDS; continuity test | Reseat/replace HVSL/SHD cables |
| Random blackouts, heat-related | Overheating, poor contact | Venting, connectors, thermal conditions | Improve airflow; rework connectors |
| Black despite power & comms OK | Failed screen/IC module | Unit presence on CAN; self-test | Replace screen ensemble / IC; code SCN |
| No reverse image, rest OK | Camera feed path | Camera power/LVDS route | Repair harness; recalibrate/update |
Diagnostic Process (Professional Flow)
- 1. Power & Ground First
- – Measure resting voltage (≥12.4 V), running (≥13.5 V).
- – Verify grounds at cluster and head unit.
- 2. Fuse & Relay Check
- – Inspect fuses feeding IC (cluster) and HU/MBUX, replace if blown/corroded.
- 3. Soft Reset & Fault Scan
- – Perform soft reset (battery negative off 5–10 min or fuse pull).
- – Run XENTRY Quick Test, note IC/MBUX DTCs, network presence.
- 4. HVSL/SHD (LVDS) Harness Test
- – Access the screen/IC connectors; check for bent pins, corrosion, pin tension.
- – Push–pull/gently flex test while image is ON; perform continuity/insulation checks.
- 5. Software Level & Flash
- – Verify software/coding status for IC and MBUX; apply updates or re-flash if needed.
- – Clear DTCs, reboot, retest.
- 6. Substitute / Replace & Code
- – If still failing: replace suspect HVSL/SHD cables, then the screen ensemble or IC as indicated.
- – Perform SCN coding & function tests.
Case Study: Mercedes A-Class W177 , Dashboard Display Not Working
Customer Complaint
A customer owning a Mercedes-Benz A-Class W177 (MBUX system) reported that the dashboard screen stayed black after unlocking the car.
Usually, the system displays a welcome animation when the door is opened, but in this case, nothing appeared not even after starting the engine.
Sometimes, after several ignition cycles, the display would return to normal, only to go black again later.
This intermittent failure affected both the instrument cluster (IC213) and the central MBUX display, suggesting a communication or supply issue, not just a single-screen fault.
Initial Diagnostic Approach
The technician began by applying the Mercedes diagnostic principle “Power, Communication, Software.”
- 1. Power Supply Check
- – Battery voltage measured: 12.18V (engine off) slightly low.
- – When cranking, voltage dropped to 10.8V, which could temporarily disable low-voltage-sensitive modules like MBUX.
- – After battery charge (up to 12.7V), display issue persisted, so power was ruled out as the root cause.
- 2. Fuse & Relay Inspection
- – Inspected fuses F222, F214, and F212 (feeding IC213 and HU6).
- – All measured 12.4V at both ends.
- – No corrosion or burn marks found.
- 3. Quick Test via XENTRY
- – DTC scan revealed:
- => A26/17 (Instrument Cluster): U111100; Communication with head unit disrupted.
- => HU6 (MBUX): U118700; No message from IC (instrument cluster).
- – These mutual communication faults pointed to a CAN or LVDS (video signal) path issue.
- – DTC scan revealed:
To learn how Mercedes technicians analyze cross-communication faults between MBUX, IC, and cameras, visit the hub article: Mercedes Display and Camera Faults: Fix Dashboard, Screen Faults.
Physical Inspection
Because both control units reported loss of communication, the technician focused on the signal and display lines (HVSL & SHD) running between the instrument cluster and head unit.
- – Panels Removed: Center display frame, side trims, and steering column shroud.
- – Connectors Identified:
- => HVSL cable (High Voltage Signal Line) carries the video feed.
- => SHD cable (Shielded High Data) ensures stable LVDS data exchange.
Observation:
- – Minor abrasion marks found on the SHD cable insulation near a dashboard mounting bracket.
- – Connector pins appeared oxidized with slight discoloration likely due to humidity.
The technician gently moved the harness while the ignition was on.
Each time the cable was flexed, the image briefly appeared, then disappeared.
This confirmed a mechanical connection fault in the LVDS signal path, not a pure software or voltage issue.
Repair Process
- 1. Cable Replacement:
- – Removed both HVSL and SHD cables.
- – Installed new genuine Mercedes cable set (per WIS wiring diagram A177540XXXX).
- – Applied proper routing and strain relief to prevent pinching behind the dashboard.
- 2. Connector Re-Seating & Cleaning:
- – Cleaned both connectors with contact cleaner.
- – Verified pin tightness and continuity (<0.2Ω per wire).
- 3. Software Synchronization:
- – Performed online SCN coding and synchronization of IC213 and HU6.
- – Updated software via XENTRY Flash Programming to latest release.
- 4. Verification:
- – Restarted vehicle multiple times.
- – Display initialized normally each time with welcome animation.
- – Performed vibration test (simulating road bumps): No flicker or loss of image.
Final Diagnostic Report
| Test | Before Repair | After Repair |
|---|---|---|
| Battery Voltage (Idle) | 12.18 V | 12.7 V |
| Fuse Circuit Voltage | OK | OK |
| Communication (IC–HU6) | Lost intermittently | Stable |
| LVDS Line Resistance | 4.8 Ω | 0.1 Ω |
| Screen Status | Black / intermittent | Fully functional |
| Fault Codes | U111100 / U118700 | Cleared |
Result: The issue was resolved by replacing the HVSL/SHD LVDS cable harness and performing a software update.
No recurrence was observed after one week of road tests and three cold starts.
Technician’s Insight
“When both the MBUX and cluster go dark together, don’t jump straight to screen replacement.
Always check the LVDS cables between the modules they’re fragile and often misrouted after interior work.
A few milliohms of extra resistance or oxidation can cause a total blackout.” Mercedes-Benz Diagnostic Specialist, Workshop Log #W177-IC/MBUX-Case2104
Lessons & Preventive Advice
- – Always maintain stable voltage when performing diagnostics or software flashes.
- – Avoid pressing directly on screen housings during dash reassembly.
- – During repairs, visually inspect LVDS cable routing for chafing or kinks.
- – Schedule MBUX software updates annually to maintain stability.
- – Keep dashboard seals intact to prevent humidity from oxidizing connectors.
Learn more about related issues and solutions including black screens, double display faults, and 360° camera failures in our central guide:
Mercedes Display and Camera Faults: Fix Dashboard, Screen Faults
DIY vs. Pro ; What’s Safe to Try
| Task | DIY Safe | Pro Recommended |
|---|---|---|
| Battery test/charge | Yes | |
| Fuse inspection/replacement | Yes | |
| Soft reset (battery/fuse pull) | Yes | |
| Reseat trim & check LVDS plugs | Skilled | Yes |
| Software updates / flashing | Yes | |
| SCN coding / module replacement | Yes |
FAQs: Mercedes Dashboard Display Not Working
1. Why is my Mercedes dashboard screen black?
Most often: low voltage, blown fuse, LVDS cable issue, or software crash.
2. Will a reset fix it?
Sometimes. If it returns, check LVDS and run a software update.
3. How much does it cost?
From €0 (reset) to €100–€300 (battery/cables/fuses) and €600–€1,400+ for screen/MBUX modules with coding (varies by market).
Author Bio
Written by Mercedes Expert
With years of hands-on experience diagnosing and repairing Mercedes-Benz systems, he brings technical depth and practical case studies to help car owners, technicians, and enthusiasts troubleshoot complex automotive issues. His work focuses on clear repair guides, OEM-level procedures, and knowledge-sharing to empower both professionals and drivers.
Last update: November 2025
— Salim, Mercedes Expert
Independent specialist in Mercedes-Benz diagnostics, CAN Bus analysis, troubleshooting case studies, and EV systems.
