Hello all! I have been browsing this forum on and off for a while and just registered today. Great place here! I wanted to start posting with this issue I have been experiencing with my 09 Silverado CC. I have had my truck for about 14 months and have about 8500 miles on it. I love it. I bought it primarily to tow my travel trailer. I bought my truck in November of 2009 and with the horrible winter we had last year I got use out of the 4 wheel drive system. Shortly after using the 4 wheel drive a few times I started getting a "Service 4 Wheel Drive System" message on the dash display. When the message is displayed I can not shift into or out of 2wd, auto, 4H or 4L. So, if I am in 4wd I am stuck in it and if I am not and need to be I can not shift into 4wd. none of the little lights on teh slector knob on the dash are illuminated either. After chekcing the manual, it says that if this message appears, turn off engine, wait a minute and restart. I did this and it seems to work. the massage goes away and the 4 wheel drive works fine. I thought it was ntohign at first. Now it has started happening more frequently. About 6 times or so in the last 6 months....even during the heat of the summer when I don't use 4wd at all. Now yesterday it happened twice. One the way to the mall for some after x-mas shopping and again on the way home...just comes on while driving. But again, I turn of the engine, wait a bit and restart....message goes away. Since the message goes away and the 4wd works I have not been too concerned. But, since it seems to be more frequent now I am worried with winter coming that I could be in for some trouble if I have an issue when I need 4wd in the snow. Any ideas what may be causing this? I did mention it to the dealer one time I had it in for oil change. they said they didn't see any codes so they couldn't do anyhting. It is very random and sporadic so I can not replicate the issue for the dealer. Doing some other searches I see that maybe it is a fuse or even a bad switch in teh selector knob? I am not very mechanical so any help would be greatly appreciated!!!!! Thanks a bunch!!!!!