HI, I have a 97 S10 Blazer LT, 4.3 V6 Vortex with 4x4. My problem is that everytime I try to switch it into 4Hi all the little lights flash and it revets to 2Hi, If I push 4Lo, the transfer case engages and off we go. Well I don't know alot about cars, but I do know that I can't drive around in 4Lo all day :-) I have read that it could be some sort of vacume located under the battery, but then I also read that 97's were not vacume controlled but instead controlled with a solenoid. I also read that it could be some sort of switch under the dash?? Please any help that you can provide me with is greatly appreciated, we have awful icey roads and way to much snow in my part of the midwest. Thanks in advance! Josie M.

 

Welcome to the forum.
I try to see what I can find. I don't have a manual for a '97.
I don't believe you have a vacuum problem. Vacuum is only used to engage your front axles.
If it won't go into 4 hi, it's either the dash switch, the Transfer Case Control Module (TCCM) or the encoder motor on the transfer case.
I'll see if I can find some diagnostics.