Why does my water damaged iPhone display a blank screen?

it sounds like one of two things to me, either corrosion is still interfering with the lcd and a good cleaning may fix it, or some transistors/ chips related to running the lcd on the board may be damaged.

My iphone 5s was rescued from the washing machine before the first wash cycle began but was sitting in a pool of water. I tried rice for 2 days, with no response from the phone. On the third day I placed it over the air vent for a little circulation. That evening Siri was working but the screen was blank. Left it over the air vent over night. Fourth day, the screen is now visible and the phone is working in all capacities but with a very mall amount of distortion on the screen. I am hopeful that day 5 will bring full restoration! Be patient and diligent. Don't charge it up until it's completely dried out. Remove SIM card to allow more airflow.

I have the same exact problem with an iPhone 4s a friend gave me. The iPhone was dropped in a toilet, immediately turned off, and placed in a bag of rice. Following this the rice got jammed in the 30 dock connector, and my friend damaged the connector trying to dislodge the rice.

The iPhone apparently still turned on, and the alarm that was set before the incident contributed to ring every morning. When my friend gave up on the phone he gave it to me. I just started tinkering with it, and decided I should replace the dock connector and see if I could get it to hold a charge, or better yet see if the screen would miraculously start working again.

After a bout an hour of charging the iPhone showed signs of connecting to my computer, launching iTunes and such, but the screen would still not turn on.

After reading this and other posts on how certain components can break based on the ph and wether the device was fully submerged etc I have decided I would give it a shot at replacing the screen.

Seeing the original post and the issues encountered, I think the damage must be so substantial that the main logic board on your device would have to be replaced.

I hope it works! Will update

I had the same problem and just got my iphone 4 screen to come to life again with a super easy fix. Not sure if it will work for everyone but it's easy to try. Same old story, dropped the phone in water, dried it out for several days in rice, charged it, and turned it on. I could tell it was working but the screen was black. I discovered that if I shined a bright flashlight at the screen I could pretty much make out all of the icons. I thought maybe turning my screen brightness all the way up would improve the contrast so I pulled up my slide-screen utility menu (I don't know if that's its official name but it sounds good) where the flashlight and other stuff is located and as soon as I touched the screen brightness slider bar my screen light came to life. It's perfect now. I hope it works for others. Good luck.

I had the exact problem and I put my phone in rice overnight. The next day it worked. Still had very visible water marks on the screen. But at-least I could see my apps. Basically I forgot my phone in the shampoo hanger in the washroom and someone else took a shower after me and the water went inside the phone. I panicked and quickly press the power button to see if it worked. It turned on and I could see the screen with serious water marks. Then after about 3 seconds the screen went black. From this point I could not see anything on the phone but it was working. How did I know? I switched the vibrate-sound button on the left side of the phone. So I knew it is still working. I turned the phone off by pressing the power button for 5 seconds then swiping right from left on the top of the phone screen. I saw this post and got a container and filled it with rice. Put the phone inside with an angle so the charging port is facing down. Made sure the entire phone was covered with rice. Then put the lid on the container. Then went to sleep. When I woke up I took the phone out and turned it on and I saw the apple sign with a white screen. The phone powered back on and works properly but has seriously visible water marks on the screen. Which I am currently researching how to get rid of. Any suggestions would be much appreciated.