The 4 wheel drive is not working on my 87 blazer. All vacuum lines are hooked up, front axels are in good shape. When you put it in 4 low you can tell it went to low gear but the front tires won't grab. And i'm not feeling any suction at the vacuum thing over on the pass. fender, if anyone has any info it's definetly appreciated.

 

R u sure the hoses r not rotten and they could be routed the wrong places, check this out. It helped me out today but if the hoses r good and they r routed the right way then u may need a new vacuum switch on the transfer case or a new front axle switch.

 

http://i11.photobucket.com/albums/a1...NV231_diag.gifheres what im talking about

 

Your vac switch is shot. On your transfer case.