If you wanted to retain the front axle locking up when the T-case goes into 4 THIS will go into the spot that the vacuum switch comes out of.
http://www.rockauto.com/getimage/get...29-0&width=450
http://www.rockauto.com/getimage/get...29-1&width=450

I'm 99% sure THIS is the proper connector for the above switch.
http://www.rockauto.com/getimage/get...36-0&width=450

Above parts found on rockauto under: 2001 Blazer - Electrical-Switch & Relay - 4WD Indicator Light Switch

Wire/Connector found under the same but in 'Electrical-Connector'

THIS is found under 'Drivetrain - 4WD Actuator Valve'
http://www.rockauto.com/getimage/get...62-0&width=450

I emailed Dorman and they tell me THIS connector/wire will fit the part.
http://www.rockauto.com/getimage/get...76-0&width=450

The parts ship from different warehouses of course so I'll get them whenever i happen to get other stuff but for $70 it'll be worth not having the damn vacuum lines plug up again

How would you hook this up and how would it work?

Exactly the same as set out by the OP but instead of going to a switch in the cab those wires head down to the t-case and hook to the first part I listed

the '4WD Actuator Valve' I'm assuming has an internal vent rather than a vent stem like the K series solenoid the OP used

Hey I got the part today and it works! But it doesn't release the 4x4 actuator it will pull it in all the way but it won't release it. You have to uplug the vacuum line to release the actuator? What's going on?

Did you put the line from the actuator on the vent side?

I put the line that goes to the actuator on the side with only one port. Then put the vac supply on the bigger of the two port on the other side just like in your pic u made

OH I made a mistake when I made the diagram... Nice catch. The line that goes to the actuator has to be on the vent side.


Edit: I will need to contact an admin to edit my original post for the updated diagram

EDIT2 : https://blazerforum.com/forum/attach...ine=1365912916

FIXED DIAGRAM

Aww I see! Thanks for the quick reply! This is an awesome mod!

Any time Sorry about the issue with the vacuum not releasing

No problem were just humans! And I got it all hooked up then my4x4 actuator got a tear in it! It's like one thing after another with this thing!