My wife had her iPhone 4S outside in the 108 degree Phoenix weather. She was under an umbrella with a misting system and the phone was misted on towards the top of the phone. As soon as she realized it, she grabbed it and wiped it down but it was too late. The screen started to blink, went blank and the LED flash came on.
I tried to shut it down immediately but got no response whatsoever. The LED flash remained on until the battery died the next day.
The headphone moisture sensor had turned pink but the sensor in the 30-pin dock connector was white as snow. The phone is out of warranty but I know that Apple is not too keen on repairing water damaged phones. I was surprised that the phone had a catastrophic failure on account that it had only been misted on and was curious to see if it had gotten wet enough to trip the internal sensors as well.
It turns out that neither of the internal moisture sensors were pink so I put it back together and will be taking it to Apple for repair.
No repair was made. Because the phone appears to have experienced water damage I have no way of diagnosing which component/s need replacement.
Apple has flat rate repairs so I will take it to them to diagnose and repair. If I knew what the issue was specifically, i.e. a cracked screen, I would repair it myself but I do not have any diagnostic tools and will therefore rely on Apple to handle the repair.
If you can't diagnose the issue, let Apple do it for you.