Power/Lock Button Not working after screen replaced

Sounds to me like you may have damaged the proximity sensor cable when you did the repair. If your brave enough to open it again look along the cable for a tear. Specifically at the curve near where it connects to the logic board.

If you cant tell this way you can take it out to check it. Search on youtube for instructions (iphone 4s proximity sensor repair) and go for the directfix one if its still there.

Check your logic board for damage, if you cant find anything the cable is most likely torn or faulty, you will need to replace it.

Search for it on ebay, ul get 1 between 16 and 40 euro depending on where you buy it from and how long you want to wait. I order from the UK if im in a rush a part, takes about a week where i am to arrive. If not i order from Hong Kong and wait anywhere up to 4 weeks. Be sure to check if there is a customs charge wherever you buy it from.

Make sure its for the 4s and not the 4 as they are different.

Apple will know if it has been opened and your warranty will be void and also your insurance if you have any.

I have the same problem and the same rubber piece left over. What is the fix here?

Your best option is to purchase a new proximity sensor cable and this will bring everything back to full working order. You can get one on ebay cheap enough. The rubber piece left just sits where i have my finger in the photograph. Facing with the slit up and the narrow side on the bottom.

That rubber piece comes from top of logic board only to guard LCD cables from getting damaged

i have the same problem, i installed a new display and the lock button isnt working. it is not stuck and i opened up the phone again to see if the ribbon cable or the logic board has been damaged but neither are showing signs of damage. please help me as this is my friends phone not mine. Im freaking out!

Daxton, There are 3 cables that connect sideways onto the logicboard. The one for the lock button is the short cable that has the long one connecting over it. Just make sure that you have plugged this cable in. If you have then check along that cable, it is extremely easy to rip that one somewhere along the way. Check it mainly on the curves of the cable. This is usually where the rip is located. If you need a replacement cable you can buy them from the UK cheap enough using ebay. Just be careful with this repair as you now have to strip the earpiece.

I checked to see if it was connected and if there is any damage, but it was connected and no visible damage. I ordered a new proximity sensor. How tough is the repair?

Well i wouldnt say its too hard but i repair them for a living. Just check youtube, there are loads of videos on how to do different repairs on them. Just remember to take your time, slower you go the better. When it comes time to put the motherboard back in place, use your screwdriver to lift the three cables that are sideways. It just makes sure you dont get the proximity cable stuck under the motherboard and have to lift it back out and that you dont pull on the cables and rip them.