I wanted to document this because I couldn't find many posts with the exact same symptoms, and this ended up being a $20 CAD fix instead of replacing the display or logic board.

Mac

• MacBook Air 13.6" (2022)
• Model: A2681
• Model Identifier: Mac14,2
• Apple M2
• 8GB RAM
• 512GB SSD
• macOS Tahoe 26.3

Symptoms

The Mac appeared to have a major hardware failure.

Worked perfectly

• Booted normally
• Fresh installation of macOS completed successfully
• External monitor worked perfectly
• External keyboard worked perfectly
• Bluetooth mouse worked perfectly
• All USB-C ports worked
• Apple Diagnostics passed with no errors

Didn't work

• Internal display
• Built-in keyboard
• Built-in trackpad

One strange thing...

The internal display would briefly work in Recovery, which immediately made me question whether the LCD itself was actually faulty.

Diagnostics

Instead of immediately buying parts, I wanted to determine exactly what was happening.

1. Apple Diagnostics

Passed.

No hardware faults reported.

That immediately made me question whether this was really a logic board failure.

2. External display

Worked flawlessly.

No GPU problems.

3. USB-C

Every USB-C port functioned normally.

4. system_profiler

Running:

system_profiler SPDisplaysDataType

Only showed my external Dell monitor.

The built-in Liquid Retina display wasn't even detected by macOS.

5. pmset

Running:

pmset -g assertions

didn't reveal much by itself, so I started looking deeper into the system logs.

6. System logs

This is where everything changed.

The logs repeatedly showed the Mac believed the lid was closed, even though it was physically open.

Examples:

SelfTrigger on Mac cannot be turned on since clamshell is closed

DisplayOn: 1, isPluggedIn 1, isClamshelled 1

policy state {clamshelled: YES, inFullWake: YES}

hasClamshell:1;
clamshellClosed:1;

This was the breakthrough.

Instead of assuming the display was dead, I started investigating why macOS thought the lid was closed.

Finding the solution

Eventually I came across a YouTube repair where the Mac had identical symptoms.

Exactly the same:

• Internal display missing
• Keyboard dead
• Trackpad dead
• External monitor worked
• Apple Diagnostics passed
• Mac believed the lid was closed

The repair?

Replace the lid angle sensor flex cable.

Apple part number:

>821-04129

Cost:

About $20 CAD on Amazon.

At that price it was absolutely worth trying before replacing a display assembly.

Installation

The repair itself is actually pretty straightforward.

The hardest part is dealing with Apple's incredibly tiny screws.

Steps:

• Remove bottom cover
• Disconnect battery
• Replace lid angle sensor flex cable
• Reconnect battery
• Boot

No logic board removal required.

macOS Tahoe surprised me

As soon as the Mac booted:

Settings → General → About → Parts & Service

reported:

>Finish Your Lid Angle Sensor Repair

Selecting it launched Repair Assistant.

It:

• Detected the replacement sensor
• Asked me to fully open the lid, and fully close the lid (at each point you wait for a beep)
• Performed calibration
• Verified the part

No Apple Configurator.

No DFU mode.

No second Mac.

No Apple Service Toolkit.

After calibration it reported:

>Lid Angle Sensor ,This is a genuine Apple part.

I honestly wasn't expecting Apple to make this repair that straightforward.

Result

Everything immediately worked again.

✅ Internal display

✅ Keyboard

✅ Trackpad

✅ Sleep/Wake

✅ Lid detection

The Mac is now functioning perfectly.

Conclusion

If your MacBook Air M2 A2681 / Mac14,2 has:

• Internal display not detected
• Keyboard dead
• Trackpad dead
• External monitor works
• Apple Diagnostics passes
• Logs repeatedly mention:
  • clamshellClosed
  • isClamshelled
  • clamshelled: YES

Don't immediately assume you need a display assembly or logic board.

Check the lid angle sensor flex cable (821-04129) first.

For me, it was a $20 CAD repair that brought the entire Mac back to life.

Edit

One thing I found interesting is that the internal display would still work in Recovery while macOS wouldn't even enumerate it. Combined with the repeated clamshellClosed messages in the logs, that turned out to be the biggest clue that the problem wasn't the LCD panel itself but the lid angle sensor subsystem.

Hopefully this saves someone else from replacing an expensive display or logic board when the real fix is a $20 cable.