GMC Repair: blowing ecm fuse, neutral safety switch, pot hole

Question
QUESTION: What causes ecm fuse to blow when you shift in reverse?

ANSWER: possible short in the nuetral safety switch?  what year and type of vehicle?

---------- FOLLOW-UP ----------

QUESTION: 1995 GMC JIMMY this problem started with once the vehicle warmed up by driving about 40km, then hit a small pot hole and the ecm fues blows. but now replace the fues start the vehicle shift the gear get to reverse and the fues blows. start the vehicle in neutral drive 40km then blows the fues.

Answer
these vehicles are typical for the nuetral safety switch shorting internally, you will probably find that when you go to unplug it, that you will have a lot of trouble getting it unplugged due to it melting inside.  The neutral safety switch is mounted to the left side of the transmission