I know this doesnt actually relate to the 6.5's but its happening on mine so i will ask. It has remote locks on it and everytime you turn the key to on the doors lock. Everytime you turn the key to off it unlocks. This would be fine other than when i open the door, reach in, and start it to let it warm up and forget that the doors lock and shut the door. irritating. I heard there was a way to stop that but no one ive talked to knows exactly how to do it. any suggestions?

That's odd. If I had to guess, (and it would only be a guess) I would have to say that is an aftermarket add on. My wifes's car, also a GM, locks a couple of seconds after you start the car, but only if you start it with the doors closed. If the door is open when you start it then it won't lock.
Since yours will lock even if you start it when the door is open, I would have to guess that it isn't factory. So, pull down a couple of kick panels under the dash and see if you have an alarm box or something up there that needs to be yanked.
Others correct me if I am wrong.

I have an after market alarm system that would do this. I was able to reprogram it so it wouldn't. I have driven some GM cars that would lock/unlock the doors anytime you shifted in/out of park, very annoying. I think the stealership is able to unprogram that feature if they are willing (could be a liability issue) and you have the cash.

Brian

I think its an aftermarket thing as well. I have factory power locks and mine doesnt lock on its own ever.

I dont know if it is factory or not. I cant find any alarm box or anything anywhere. a friend of mine has a 98 tahoe that does the same thing. If the door is open it usually will not lock but occasionally it will and this is when i have problems. I dont know if there is a sensor telling it whether the door is open or not that is faulty or what. I guess ill just have to pay attention for now. thanks guys!

Sounds like a magnetic "hide-a-key" might be a good investment....

can always take it to a car alarm place to see if they might help out. my two alarm systems i think were stealer options and came with little manuals to reprogram them which i havnt yet done. havnt run into a problem like whats described here

My subaru beater car has this. It's an aftermarket alarm system. Key on doors lock. Key off doors unlock. It never did this before the alarm system was added in. The newer GM's have this feature. AFAIK this didn't come stock on our trucks.

ok thanks guys and yes the ole magnetic key has come into the picture lol