94 bravada heater issues?

Ok year old heater core and blower motor. I did it myself and messed something up. It's really loud on the outside when the fan is on. I can feel air coming out of the gap where the hood hinge is. Barely anything comes out any of the vents. It dosen't seem to matter what setting it's on alittle air comes out of everything. I took the dash almost all the way off again and couldn't feel any air blowing in wierd places but I did rehook the wiring for the mirrors so that's nice but makes me think I missed something else. It could be a vacume issue in the controls but how do you test it? any healp would be great, I have asked about this truck before and got some great info thanks.

Ok year old heater core and blower motor. I did it myself and messed something up. It's really loud on the outside when the fan is on. I can feel air coming out of the gap where the hood hinge is. Barely anything comes out any of the vents. It dosen't seem to matter what setting it's on alittle air comes out of everything. I took the dash almost all the way off again and couldn't feel any air blowing in wierd places but I did rehook the wiring for the mirrors so that's nice but makes me think I missed something else. It could be a vacume issue in the controls but how do you test it? any healp would be great, I have asked about this truck before and got some great info thanks.

One of the first things to check for is good engine vacuum to heater control.

Ok but where do I hook in and how much should I have?

Ok but where do I hook in and how much should I have?

T a vacuum gage into the engine vacuum line to/close to heater controls.
You should have full engine vacuum there.
If not hook it direct to line to engine and see if same reading.
17-18-20 ln. vacuum.

If low there and you have good engine vacuum on intake/engine trace it back to the intake/engine and see where you are losing vacuum.
Lot of problems with the plastic line and fittings and vacuum balls/tanks under hood and where it hooks to engine..