Hi i have a 1998 Blazer ls model i have been working on my 4x4 for the last week press 4hi or 4llo and it just clicked reset battery it just flashes then goes back to 2hi. I pulled computer out of kick panel cleaned prongs and put dielectric grease did nothing but flash then back to 2hi. So i took battery tray out diaphragm was sucked in all the time. Changed vacum switch electrical and the vacuum one press 4hi or 4lo flashes then back to 2hi idk what to do now its very aggravating! Please help me!

 

Have you trased out your vacuum lines to be sure they are not switched?

 

No I have not I don't know which ones go where

 

Have you checked your t-case vacuum switch? The one in my 04 was borked into the 4wd position leaving the front axle locked up all the time and broke the shaft in the stub tube. This is not as common as having it break in 2wd mode.

 

Yes I changed the vacuum switch on the t case and did nothing the 4ho or 4lo just flashes and never engages

 

Odds are pretty strong that it's your t-case encoder (shift) motor. To know for sure, there is a diagnostic procedure you can do that is fairly simple, which identifies the trouble codes that are stored in the TCCM. Take a look in the 4x4 article in the DIY section, starting with thread #5.

 

If that is broke and I have to replace about how much does that cost

 

try pulling fuse 13(I believe) lettin it sit then replace --this resets something , either the pushbutton set or the encoder not sure but it sometimes worked for me

 

This will reset the TCCM (clears out the trouble codes). As for the cost of the encode motor, look here.