Keyboard is no longer backlit.

Keyboard is no longer backlit. Had a problem with click key not clicking, took it to the local Mac store 9/21/11 and they replaced the top (around the keyboard which includes the click key and the speaker grills) of my MacBook Pro (early 2008). Click key now works, but keyboard backlighting does not. However, I am not sure when backlighting ceased. Before repairs (but after installing Lion), immediately after repairs, or more recently. I seldom use the keyboard in dim light. I noticed this a couple of nights ago and have been looking for a solution since.

Any suggestions on how I can get it working again?

Thanks.

P.S. Extended warranty expired 9/21/11.