My solution to ambient light sensor problems with keyboard and display

Question

Level 1

32 points

My solution to ambient light sensor problems with keyboard and display

*Problems covered:*
-> ambient light sensor not working at all
-> light sensor only works for keyboard illumination but not for display brightness
-> light sensor only works for display brightness but not for keyboard illumination
-> keyboard illumination works the wrong way round (ie. gets dimmed when room darkens)

Occurences:
-> after migrating an existing user account from another Mac
-> may occur on freshly installed MacBook Air with no account migration
-> after wake from sleep

Solution:
-> create a new user account named "test" with password "test"
-> make sure this user is allowed to administer the computer
-> log out and then log in as user "test"
-> open the Terminal and type this one line command:

*sudo cp ~/Library/Preferences/com.apple.BezelServices.plist /Users/YOUR USERNAME/Library/Preferences/*

-> replace "YOUR USERNAME" with the short account name of the problem account
-> enter the admin password ("test") which will not be shown
-> log out and log in again using your own account
-> you may now delete the user account "test" if you want to

The ambient light sensor will now work properly on both the display and keyboard.

*How to test if your ambient light sensor is operating properly:*
-> make sure you are in a well lit (full daylight) room
-> make sure you enable "Automatically adjust brightness" in the Displays system preferences
-> make sure you enable "Illuminate keyboard in low light conditions" in the Keyboard system preferences
-> set display brightness to max using the F2 key
-> set keyboard brightness to max using the F6 key
-> hold your hand over the tiny holes to the left of the iSight camera
-> the screen will now slowly dim and the keyboard will now slowly light up

*Bug remaining:*
When putting the MacBook Air to sleep in a well lit room, and then waking in a dark room, the keyboard illumination will work the wrong way round. This should be solved by Apple in a future software update.

You can work around this by always waking and sleeping your MacBook Air in a well lit room.

Message was edited by: Colpolyp

MacBook Air

Posted on Mar 1, 2008 3:32 AM

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Answer 1

Mar 1, 2008 1:01 PM in response to Colpolyp

Glad you found a solution. However, when I put to sleep in well lighted room and wake in a dark room I don't get the backlighting working in reverse.

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Answer 2

zzbar

Level 1

26 points

Mar 2, 2008 1:53 PM in response to Colpolyp

I followed your one-line instruction and it fixed my two migrated accounts' backlighting problems. Thanks very much.
After I did this, I noticed that my F6 key is no no longer functioning, ie. when pressing F6 key, nothing happens and a white circle with a slash over appears. Is this normal? I guess i don't need to use F6 key to adjust the backlight anymore (it does so automatically now).

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Answer 3

Mar 3, 2008 12:45 AM in response to zzbar

The slashed circle appears when you try to adjust the backlight somewhere where the light level is too high. The backlight will not come on at all if the light level is above a certain amount. Try it in a dimmer place and it should be fine.

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Answer 4

gmacsjd

Level 1

0 points

Mar 4, 2008 10:10 PM in response to Colpolyp

hello,

i am experiencing the issues where the keyboard backlight is reversed. i followed your instructions to the letter, and it didnt work for me. any other ideas?

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Answer 5

Mar 5, 2008 4:50 PM in response to Colpolyp

I don't have a "com.apple.BezelServices.plist" for either my original user or the test user to copy from in the location you specified.

Any suggestions there?

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Answer 6

dudup

Level 1

4 points

Mar 12, 2008 7:31 PM in response to Colpolyp

I did noticed that it does get confused with mid terms of room light. If you just put it on a completely darkened room, or a fully lit, it will adjust it self accordingly.

My advice is to let the machine decide those settings. If you don't force anything, it will find the right setting on extreme conditions.

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Answer 7

pketh

Level 1

0 points

Mar 27, 2008 12:45 PM in response to Colpolyp

I also don't have the bezelservices files. Is there someplace we could just download them or someone willing to host em up?
Would dropping them into the directories and then following the OPs original steps work to solve the problem?

thanks

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Answer 8

webdz9r

Level 1

0 points

Apr 23, 2008 8:45 PM in response to Roderick Thomas

The above instructions do work but you must follow them to the TEE. Knowing my way around the unix command line I tried a the following shortcut. Created test user, tried to copy the file and it wasn't in the test users directory. So I logged in as the user (as the directions stated) and logged out and back in to my main account. I copied the now present file from the test account and logged out and in and again it didn't work. It only works when you create the test account, login as the test user and execute the command. There is something about the file only working when you're logged in as the test user.

So again create the test account, logout of your main account and login to the test account -- copy the file and logout of test and into your main account and it should work.

-- NOTE --
My test account wasn't in the sudo users file so I and to su - <your main account> and copy the file from test to your main account -- This is somewhat because i have my root account login enabled. by default this action isn't required but might help some people.
-- END OF NOTE --

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Answer 9

Apr 24, 2008 4:27 AM in response to Colpolyp

Oh woe is me. Created the new user, logged out and now the login items are inoperative. Rebooted and no joy; still inoperative.

Whatever migration asst. does to screw up the 501 user it appears to do royally.

Made a TM backup of the Air just last night ... so here's to my first test (if I can figure out how to break in, or worst case re-install disks and migrate asst (ugh) from TM backup).

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Answer 10

Apr 24, 2008 4:30 AM in response to David G Chapman

Using the and cursor keys worked to get me logged in.

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Answer 11

Apr 24, 2008 4:41 AM in response to Roderick Thomas

In the "test" user, go into a darkened room and play with the display brightness and ambilight settings until you have a good balance.

Shutdown and restart.

Log back into "test" and the OS should have built a BezelServices.plist for you.

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Answer 12

Apr 27, 2008 9:30 PM in response to Colpolyp

Thank you! I was afraid I had screwed something up installing my EVDO card! Fix works beautifully. Hope to see an Apple Update soon though!

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Answer 13

Apr 29, 2008 12:18 PM in response to Colpolyp

I am having the same issue as well, followed your instruction and it worked 1 time.
i have 2 users we will call user(issue) and test(works fine)
i had copied over the file from test to user and it worked 1 time
if i log into user the als does not work
log out and tried it at the login window and does not work
log in as test works fine
log back out and it works at the login window fine
log in as user and it does not work

any other idea?

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Answer 14

Jonny8

Level 1

0 points

May 3, 2008 1:02 PM in response to T Poulter

same problem here.

I even looked the plist up and copied it via an usb stick to the issue account, funnily, when I said overwrite the current plist there were still different settings within the plist in the issue account then in the test account, so i deleted the plist and then copied the "good" plist in, that worked as far as the settings seem to be same, but it still doesn't work.

don't know what else to do!

Thanks for your help

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Answer 15

May 7, 2008 5:16 PM in response to Jonny8

tried the fix...worked once in my "issue" account, then back to before 😟

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