Attempt to repair fan, logic board will not turn on.

Yesterday, my friend send his laptop to me to fix his mac book pro 13' 2012 unibody. I took it apart and look at the fan that is not working well. So i tried heating up the fan using a heat gun without the logic board (i took it apart), it went a little faster, but then the computer shuts off and will not turn on.

plugged in the magsafe charger, it stays green, battery is half when the left button was pressed, SMC reset only blinks the MagSAfe LED for a milisecond, but stays green