Chosen Solution
I’ve noticed the bottom left corner (on the back) to be slightly warm under moderate usage, but recently it seems to be warmer than usual. Wifi strength is really low (1 bar) even when right beside wifi router. I don’t have any wifi security enabled on the router. I restored through iTunes and still same problem. Nothing internal was changed between when it was fine and now nor was anything changed on the wifi router. Everything else works without issue. Parts I’ve replaced a few months ago: battery, back cover, digitizer, lcd, headphone jack.
well, not a wire per say, but skippy has the right idea. maybe there’s a short somewhere along the board. when you have free time you should open up the device, disconnect the battery and give the unit an iso-propyl alcohol bath (use a soft bristle brush) Rinse with iso when finished and let dry thoroughly, then when done let it dry some more :) re-solder and let me know your results.
There could be a short causing problems with the wifi and heating up the back. You should make sure that there are no stray wires touching the back.
