Hi everyone! I need some help. I am thinking I have a vacuum leak. The AC only comes out of the defrost unless I turn on the 4x4. It worked perfectly fine until bulletproofed a couple months ago. Pump is working fine. Replaced PVH solenoid since it looked like it ran through a garbage disposal. Can’t find any leaks in engine bay and reservoir is holding pressure. The only place I found air was under the dash by a plunger type of deal. Not sure if that’s normal. If it isn’t, is there a way to repair without having to replace the whole evaporator unit? Cold air leak highlighted in pic.