Latitude E5420 Keyboard Backlight replacement problem

Hello All,

I have a question about mij Dell Latitude E5420.

My model doenst have a keyboard backlight, i have another E5420 for parts, this model has a backlight option, that keyboard works fine, but when i install that one in my laptop the backlight burns but when iam in windows no key works, i rechecked al connectors, everything is fine.

I found out that my parts laptop has extra mouse buttons above the touchpad and a mouse nipple on the keyboard.

The model i use daily just has a normal touchpad and no nipple.

Can somebody help me top get the backlight keyboard working in my E5420, they are both exact the same model, only one has more options i guess.

Thanx in advance,

Koos