I just recently purchased a 2002 chevy trailblazer, 127 k miles. My question is regarding the 4 wheel drive. All lights on turn **** for 4 wheel drive light up at start of vehicle, and also illuminate for 2wd, awd, 4hi and 4 lo when turned to selection. My 4 wheel drive is not engaging. We have taken fuse # 8 out to let it reset and replaced. When I switch from 2, to awd to 4 hi I hear a air noise come from under vehicle. Is this normal? What could my issue be? Transfer case fluid? Reset something? If my 4wd was bad, wouldn't a light appear blinking?- Please help with any hints. I don't understand why its not engaging?