When we push the 4wd button on the dash u can hear the accuator cycle and the 4hi light stays on, the same goes for the 4 lo, when in 4 lo u can tell the gear ratio has obviously changed as well. The problem is the front wheels arent pulling. Actually havnt used the 4wd since last winter and it worked at that time, this is a 95 blazer, any help is appreciated ,thnx. Reply on this forum or feel free to email me...[email protected]

 

There's a vacuum switch with 3 vacuum lines attached to it on the transfer case. Driver side, inboard and slightly above the front output shaft.


When you select 4WD, linkage inside the transfercase operates the switch, which applies vacuum to an actuator under the battery tray. The actuator pulls a cable that is attached to the right front axle tube, which engages the right front axle to the front differential, and 4WD becomes operational.

With the engine at idle, 4WD selected, transmission in park, make sure the actuator has vacuum when 4WD is selected. The cable should pull in about 3/4". Post your results.

 

Thnx for the help, I found the vacuum line under the battery at the actuator was completly off, i could hear it sucking air when my son would push the 4wd button. I dont think GM intended on a grown man getting his arm and hand to that actuator to reconnect the vacuum line....lol

 

Glad you figured it out, so everything is working now?

 

For me it might be on the transfer case, I can hear the relay clicking, but all that happens is the 4hi light will flash a few time then back to 2hi.