Instead of guessing, read these. Study them carefully and then ask any questions that you might have.

You have a 3-button NV233 system. It's operation/diagnosis is different than the 4-button NV236. Don't confuse them.

https://blazerforum.com/forum/tech-a...ill-help-7180/

https://blazerforum.com/forum/tech-a...gnostics-7683/

https://blazerforum.com/forum/2nd-ge...-blazer-89670/

Best wishes for a successful repair

 

So I got my 4 wheel drive to engage but the front tires still don't spin. Any ideas?

 

You say you got the 4 wheel drive to engage....Is the Tcase driving the front drive shaft ?

 

What I think it might be is either the T-case switch and or a vaccum leak

 

If you think it is the t case vacuum switch, you can always pull the cable manually and see it the right front wheel locks. If it does, the problem is on the vacuum side of the 4wd system, if it does not, it could be the front axle disconnect system has a stripped gear or the drive gear from the diff to the front axle disconnect.

hopefully yours is simple. Mine is the front axle disconnect that is the problem and I will be rebuilding it shortly.

Good luck//