E5570 Backlit keyboard not working

Hi,

I have a Latitude E5570. It did not come with a backlit keyboard. I purchased a dell laptop keyboard with backlit function. Installed it fine (noticed the extra ribbon cable that I assume is for the power for the backlight.

The F10 key includes the FN icon to enable backlight. But it is not working. Checking the bios, there is no setting as per the manual to enable the backlight. There are the two settings for how long before it times out either on AC or battery though.

Does anyone have any ideas? Is there a dell software I can install on windows 7 to enable this?

Thanks!