Doors locking on their own!

[Gone Again]

Have had it happen 4 times since new on my 2010 GMT-900. The key was left in the ignition, but not always all the way in the ignition. It was out far enough so the chime didn't go off. The horn would chirp once and the doors would then lock. The last time the doors were all opened as I was cleaning the inside. Very strange. My buddy has 2009 GMC and his has done this also. Wondering if this is happening to others. Never has happened with key out of ignition. Taking it in this week as it goes out of warranty March 1. Will post what they find if anything.

[StinkyCheese]

Dad's 2009 Sierra did this to me one morning when we were packing up to go fishing. Scared the crap out of me thinking the darn thing locked the keys in the truck. Thought I was going to have to wake my dad up @ 4am to either drive 45 minutes to open the doors or call on star and have them do it. Thankfully the passenger door was still open. I do this all the time in my 2006 Silverado and it never locks the doors.

[hodges25]

Did you hear 3 chimes in a row while cleaning? If you hit the lock button once while the doors are open the truck sets up to lock all doors and set the alarm 5 seconds after the last door shuts. It's in the manual if you want to look it up :-)

[Badass69]

2011 and 2012 Suburbans used a crew vehicles on a job I used to be on did the same thing. A single chime, no one in the truck and the doors would lock. We had it do it with the window open and no one in it, not to mention the only set of keys for partially pulled from the ignition.

 

Like everything else GM dealers just said they couldn't replicate it and or it was normal.