Hello, I have a 1996 Blazer that will not lock in the front wheels. I can hear the motor on the transfer case working. front driveshaft is spinning. I have 16 inchs of vacuum going to the actuator switch on the transfer case. When I push the button for 4 high it only has 2-3 inchs of vacuum on the line going to the front differential actuator.No leaks I have replaced the one on the transfer case Approx 3 months ago. there is no fluid in the lines. I can hook up a vacuum pump to the front actuator and get it to lock in. All vacuum lines are good. just does not have enough coming out of the switch on the transfer case. could the shift motor on the transfer case cause this or did the vacuum switch on the transfer case go bad again? Thanks

 

The '96 is a bit different than my '02...but are you saying you replaced the vacuum line between the t-case switch to front actuator or did you replace the switch on the t-case?

Sounds like the switch is not moving enough to allow full vacuum and thus pull the actuator to lock the front axle. Did you measure the 16" on the line at the switch? If not then make sure this line has no restrictions.

It may be that the new switch you put in has failed. If you bypass the switch will the front axle lock?

 

Changed the switch on the transfer case again and solved the problem