Help me identify this input

[angrynerdrock]

Looking to add a backlit keyboard to my Dell Inspiron N4110 laptop. I found via googling someone on a message board saying they were able to do it but didn't go into anything else.

This is a picture of the laptop motherboard. The input I've circled is hidden underneath the plastic shielding underneath the current keyboard. All other inputs are exposed and have ribbon cables to them, but this one doesn't seem to have anything plugged into it.

Here is a back lit keyboard that should fit:
http://i.ebayimg.com/images/g/TVkAAOSwa-dWq~Oc/s-l1600.jpg

The big cable is the keyboard itself, which is exactly the same as what I have now. The small cable is the backlight. The orientation going straight down and it only having 4 wires makes me believe that input may very well be for the backlight. If so, I can cut the plastic covering it, plug it in and I'm happy.

Don't want to ruin my laptop though. Can anyone confirm what this connection does? I tried looking online but I'm coming up at a loss.

 

[angrynerdrock]

Did some additional digging, found these schematics. There is a section titled Key Board Illumination, and its a 4 pin connector
http://www.s-manuals.com/pdf/motherboard/quanta/quanta_v02,_r01_r1a_20110119_schematics.pdf

Then I found the Dell Vostro 3450 is pretty much the same laptop, and uses the same motherboard and does have a backlit keyboard option. The biggest difference being a 6 pin ribbon connector to the left of the one I'm questioning, but its oppositely oriented, so i highly doubt thats for the backlight
http://i.ebayimg.com/00/s/OTAwWDE2MDA=/z/Li8AAOSwyjBW2d0C/$_57.JPG?set_id=880000500F

The keyboard i ordered arrives today. I think I'm pretty safe. But anyone versed it reading schematics, if you could look over id really appreciate it.

 

[Mr Evil]

The schematic says there should be a MOSFET, two resistors and a capacitor nearby, and indeed I think I can see those in the photo inside the circled area.

Do you have access to a multimeter? If you do, you should be able to check if pin 1 is connected to 5V_RUN, and that the resistance between pin 2 and ground is about 300k.

 

[angrynerdrock]

I had a good feeling about it so I went ahead and took the plastic covering off. I probably could have done this much cleaner (and I plan to sand it soon to clean it up). I took a soldering iron and melted the plastic to cut through it quickly.

I followed the seams that were already there in the plastic. I probably didn't need to cut this much off, but oh well.

The connector is labeled J6, the connector on page 30 of the schematic is J6. We are in business Don't have a multimeter, but judging from the schematic, and the Connector label i believe Im safe.

 

[angrynerdrock]

It worked, phew.