Hello everyone this is a great site with tons of info. I purchased this blazer for my girlfriend and I have been trying to resolve this problem. I have read all the threads about these problems so let me add mine and get your opinion. When the truck is sitting and running in drive I push the four wheel drive button and it flashes then lights up service four wheel drive. But if I drive the truck and hit the button at let's say 20mph it works fine. But then if I sit there in N and try to hit 4 low it flashes service four wheel drive. What's your thoughts? Thanks for you help