I had a deficient battery for the last two weeks that kept rapidly draining and shutting the phone off. AT&T sent me a replacement on Saturday, and it's worked fine since then.

Yesterday, I upgraded my OS from 4.2 to 4.5.0.55 and ever since then, I've had issues with a sporadic keyboard and trackball light. Sometimes it won't even come on for hours at a time, other times when it does come on it doesn't last long. As of right now, it hasn't worked all day.

Any suggestions or ideas what's going on?

That's strange. How is the lighting when you notice this?

Place your finger over the LED and see if they emit light.

Here's something I just noticed...

When I have the phone out in the light, the trackball and keyboard do not come on. I then took the phone and put it under my desk in the dark and they both came on. I let the screen shut off and brought it back in the light and turned it on again and they didn't light up, but they did again when put back in the dark.

However, this morning when I went to first use my phone, it was dark in my room at home and they did not come on.

The LED is also a light sensor. That is why you notice them coming on under your dark desk and not coming on in the light. Was there any light in the room this morning?

No, it was pitch black.

Is there any way to change this setting? I'm used to the trackball light coming on all the time when using the phone, whether it be dark or light out.

there is only an 'on' and 'off' option for the backlight, unfortunately there is no sensativity setting...

I've started to get used to it now, I also love how the screen becomes VERY bright out in the sun now. That's a huge improvement, and I'm really starting to like the light sensor for the trackball as well.

I think I'm in love with 4.5.

Although there is a brightness setting. I have mine at 100 and like it a lot.