N-75 no vaccuum

Car has had little to no boost for a long time. I thought that I may have had sticky vanes, because sometimes it will get boost, but very unresponsive and rarely will hit 14 psi. On a good day it will make 2-4 psi. I did the Mr. Muscle oven cleaner. A couple of days ago, I went to take the turbo apart. I noticed the piece that moves that the actuator rod attaches to, moves freely as it should. I stopped and put it back together. There was a code P1158 if I remember right, that didn't allow me to pass the emissions test. I had another map sensor, swapped it today, and the code went away.

Actuator line and actuator itself tested good. Line held vaccum. Arm started to move around 4 on the gauge and fully extended around 14-15 on the gauge.

Switched line going to actuator from N-75 to N-18. There was no change.

With the car running at idle the N-75 puts out NO vacuum, and the actuator doesn't move which would explain why there is no boost.

I disconnected the vent hose going to the airbox at the airbox. I could blow through it. There is either a leak, or you are supposed to blow into the tube that direction?

Cars brakes work like they should (power brakes are working fine)

If the N-75 (checked arm, and with vac gauge) and N-18 (didn't check arm, drove and no boost though) are not putting out any vacuum, what could be the cause? What makes the N-18 and N-75 put out vacuum?

What is the vacuum reading at the small nipple coming from the vacuum pump's check valve? Is it a solid 25-28"hg at idle?
Start there. Then follow the vacuum source all the way to the N75 valve. It should be that same reading to all the vacuum operated valve components.

There could have been something that has blown a fuse to the power source for the N75 if it is getting vacuum. I'd have to look up which fuse.

If there was ever a hole in the actuator diaphragm or vacuum reservoir was leaking the system will suck in dirt and clog the N75 innards.

If the system goes into limp mode it will also tell the N75 to vent vacuum to the atmosphere. Try the vacuum going to the turbo actuator after doing a restart of the car.

^^^exactly
Simply broken lines or bad pump if n75 n18 swap didn't do anything, or both are bad.
Unlikely. ..

Vacuum ball should be checked to make sure there's no cracks too.

I would replace all vacuum lines if vacuum is good at the pump.

Check fuse #34 at the cars inside fuse panel

Before you get the turbo working again, BE SURE TO DRAIN THE AFTERCOOLER, Otherwise you'll suck a load of oil into the intake and have a runaway.
You don't want this.

Solved with your help! I started checking rechecking vacuum by the N-75 and got 4" everywhere instead of 0 which I thought was strange. #34 fuse was good, vacuum ball was good. Then went to the check valve or whatever is by the intake manifold like JETahh recommended, and the very first line was cracked where it sits in the hose loom before it hit the Y! Replaced it, drained the intercooler, and hit the road. I am so happy my car running is right again

Glad you got it fixed.
Replace the vacuum lines to avoid further issues.

2X ^^^
Replace all the vacuum hoses one at a time.
ID Parts has a kit with the 2 sizes and lengths you need.