GMC Repair: 2002 gmc evnoy pcm1 fuse, fuse blows, circuit breaker

Question
every time when trying to turn key into run position the pcm1 15amp fuse blows  i have changed the alternator and ignition switch any thoughts what may be causing this to blow,also wants it blows if you turn the key to the run position there is a ticking sound at the top of the engine

Answer
Hi
It is eithe one of the ignition coild or one of the injectors.
That is ALL that fuse feeds.
It COULD be a wire pinched somewheres, so I would unplug 1 injector at a time, see if it blows and one coild at a time until it stops blowing (You can use a short finder circuit breaker for this process).
Thats where I would start.
I Hope this helps.
GOod Luck
Pawl