Air's don't offer combo audio analog/digital output/input ports so you won't see the red glow from LED.
Have you used the headphone socket to connect ear-buds, headphones or external speakers extensively to? Did you loose the sound after using the headphone socket?
Have you tried hitting the Mute hotkey F3 (older kbd) /F10 (newer kbd) and the hotkey volume up button F5/F12 a few times. Does the speaker Icon show up on the screen and have the maximum waves shown? Any sound coming out of the speakers when you do this? Check the system Prefs > Sound make sure you have Headphones selected and the volume control and Mute settings are correctly set.
If that doesn't work you may want to try to reset the SMC
See Apple Tech Note: http://support.apple.com/kb/HT3964
At this point it sounds like the headphone socket switch is broken and will need repairs
This happened to me. The mute was staying grey. I tried zapping the PRAM and got it to work once. Then I bought a new audio cable here on ifixit. I was nervous to install it because I know NOTHING about fixing computers. But the instructions were super clear and I did it in less than an hour. AND IT WORKED!
I was so happy to hear that chime when I turned it back on!
I just ran into the mute stuck problem with my mid 2010 MBP. What's funny is that the power comes back on and there IS sound, unles there is a different speaker for the start up chime. But anyway, my issue... Muted spound problem; No red light.
I looked at different solutions:
- insert something possibly (but w/o a red light I didn't want to try)
- Reset the SMC (it didn't help)
- Repeated in/out of head phones (didn't try but 3x's figured it would offer little success)
- FIND A FRIGGIN' REAL FIX through the keyboard command (which I found mentioned by chance some where else)
Now I have it.... IT'S SIMPLE These are the initial directiions...
power off >remove all peripherals > remove battery > hold down power button for 10 seconds > re-install battery> hold down APPLE/ALT/P/R hit power hold down for 4 cycles.
What I did for my MacBook Pro was only part of the directions...
power off >remove all peripherals > hold down power button for 10 seconds (once it chimed on) > immediately held down APPLE/ALT/P/R hit power hold down for 4 cycles.
When it came back to life everything worked great!
Hope this alternative works for those that still had the isue or it comes back again. Although for some people it could also be dust build up in your audio port hole. Use compressed air (but in the upright position of course to not freeze the inside of port damaging something)