Goes into sleep mode upon boot-up, following spill recovery

Well, I spilled about 2 ounces of tea on my MacBook (in the upper left-hand corner where the chips are) - and it went dead in about 6 seconds, before I could grab and turn it upside down. I disassembled, removed RAM and blotted up the few drops of moisture I could find, blow-dried it, and let in sit 24hrs in open air. I then reassembled.

On AC power, with a full-charged battery, I get to the chime-tone, and see the OS X box with the loader bar, then the screen goes dark and power light blinks, apparently going into sleep mode. If I hit the spacebar, the DVD drive makes the normal sound and the power light stays on for a few seconds, then goes back to sleep mode. (The screen stays dark.)

Where is the sensor that puts the system to sleep? Might this be shorting out? Any other thoughts? Thanks in advance!