first off, Hello. New member here. I didn't want to hijack or revive an old thread. I just purchased a 2000 Blazer ZR2 and it will not lock into 4 lo. The light blinks for about 15-20 seconds and then returns to previous setting. It is a 4 button with the 4wd auto. I have checked actuator under battery and it appears to be working fine. I have looked for the transfer case vacuum thing and cannot find it. Any help would be greatly appreciated. All other drive modes work fine 2hi 4hi. Also the light on the instrument panel that tells you what gear you are in does not work. Could this be failing to tell computer that I'm in neutral and not allowing 4 lo to work?