I have a 2008 Uplander LS short wheel base. I'm not sure if this is just a coincidence or not but this started happening after I installed an aftermarket stereo with one of those magic boxes to retain factory chimes. When I open the driver's door to enter the vehicle my chimes will usually sound twice. I've only had the vehicle a short time but I don't remember it doing that when i first got it. Sometimes I will put the key in the ignition and start it and the chimes will not stop sounding. I have to turn it off and take the key out. And sometimes that doesn't work so I need to put the key back in and fiddle with it then take it out. Sometimes when it happens I will get the cluster warning that the key is in ignition even though it is not. So far I have been able to fiddle with the key to get things to operate as normal but I'm worried that will soon no longer work. I would assume this is some sort of ignition switch issue but the fact that it chimes twice when I open the door to enter makes me think twice. Has anyone dealt with this before? Or maybe on a different vehicle? Is this a common GM problem?

 

replace the ignition switch and go from there.
Chimes are produced by the "magic box"

 

Same thing happen to me as soon as I took my battery out of my key fob it stopped. I thought my subs and amp were making it do that cause I also have a toggle switch for my amp and head unit that need to be off as well manually but even if them off was still like locking it and honking like on and off while I was driving it would effect it. But I would try that it helped it stop for me but good luck! And hope you got it figured out by now have a great memorial day weekend!