Most of the time, my doors lock and unlock normally and the alarm sets like it's supposed to. Occasionally, like this morning in a crowded parking lot, when I locked the doors they immediately unlocked and the alarm starting going off. Tried the alarm reset by locking/unlocking 3 times, no help. By the third lock cycle only the driver door was locking. The alarm finally shut off, not sure if it was something I did or just sounded long enough, then the doors locked normally again. Any ideas? Would a door not being fully shut cause this? First time this happened was when I went to Phoenix a couple months ago. Has happened twice in the past 2 days now.

 

On a DI when the alarm goes bad they truck wont start, it will either not crank or will crank but not start due to the fuel pump kill.
Then it will just shut off for no reason while driving, re-start and fine.

I think you have a different issue.
Check the under the hood alarm switch, if it is mis aligned it can make the alarm think that a door is open.
Other than that check all the other doors to make sure that they are closed/aligned properly.

 

sounds like an actuator didn't lock correctly, thus causing the doors to unlock and set off the alarm, or possibly a door trigger not working correctly making the vehicle think a door is still open, I would take a closer look at each door lock (manually test them and see if any feel tight), and pop out each door pin switch to make sure they are not broken inside the switch.

 

AK,
Call me and I'll walk you thru this one, should be easy then you can report back what was wrong.