I just bought a 2005 colorado 4x4, and the 4wd does not work. When you start the pickup, all 3 lights of the 2 Hi, 4 Hi and 4 Lo lights flash on, then go off. There are no lights on while running. If you push the 2wd or 4wd button no lights come on, but you can here the transfer case motor run. I have replaced the switch on the dash, the transfer case motor and the front end disconnect with no luck, if you take the transfer case actuator out you can lock the transfer case into 4 wheel with a screwdriver? Front wheels do not turn with front end off the ground. Any help will be greatly appreciated.