You have the Timer = millis() and the related IF in the wrong place.
The way you have it the value in Timer is updated just before the IF so it can never be different by 15000 msecs. (That's 15 seconds, not 2 seconds, by the way).
Look at how millis() is used in the sketch attached to the first post of this Thread. Then if you are still stuck I will try to help.
...R