i have a 1999 blazer lt with autotrac 4x4,when u switch it from 2hi to 4hi,4lo or auto the lights on the buttons keep flashing but if u switch it back to 2hi it will flash 3 or 4 times and then stay solid like its supposed to,what would cause that?

 

My guess is the front axle. It's either not engaging or the switch is bad on it so the TCCM doesn't "think" it's engaging. Keep your finger off the 4 LO until you find the problem, that's a nasty range to get stuck in if it's the encoder motor failing

 

i didnt think of the encoder motor the day it happened and i put it in 4lo and it felt like it engaged,it felt like it had a lot more low end torque after putting it back in drive but the light would never stay solid... i dont know if that helps at all.............the truck is my girlfriends and i dont know very much about chevys 4x4 system except that i hear its a pain in the *** and a very bad design,i have a 99 explorer its alot easier to work on...