99 Blazer 4x4 Not Working pulled the bat box up and boot looks fine.. vacuum line was off so put it back on and went to engage 4x4 and still nothing.. it clicks and 4x4 button blinks 4low blinks then 2wd light stays on. Truck was in ditch and ever since 4x4 has not worked.. Transfer case clicks in 4low and high but front wheels dont engage. Not shure what it could be anyone have any suggestions.

 

Have you checked for clean connections at the encoder motor on the transfer case and at the TCCM located behind the passenger side kick panel?

Do you have the 3-button (NV233 - RPO NP1) or 4-button (NV236 - RPO NP8) switch in the dash?

Check out the Tech Article (DIY) Index link in my signature for some articles that may be of some help.

 

Its a 4 button and am going to check the conections now.. thanks ill keep you updated.

 

With the NV236 transfer case, there are additional checks you can run through if you have a scan tool capable of communicating with the TCCM... Not something everyone has access to though.

 

Figured it out was a vacuume line.. BUT my blazer must have gotten jealous when i tried mine it seems to not work now.. We took out the bat box vacuume pump seems good but it will not engage at all. it is a 97 chevy blazer tried checking fuse under dash but cannot find other fuse box. It is the 3 button switch. Not engaging what so ever my buddies would engage low with 2wd but front tires where not spinning but now mine seems to not want to do anything at all the light just blinksl.
Any ideas.