I turn on fan switch can hear fan running but no air to cab

 

Something you might want to check is for a stuck or not working directional door motor assy in the duct work.


If your vehicle stays parked outside ,sometimes rodents will build a nest and manage to block the passages.

 

I have no idea what your vehicle is. May be something as simple as a loss of vacuum or electrical to an actuating motor to a blend door within the heat box. I have dealt with rodent nests before. Everytime, nest material would blow out of the duct work from the intense flow of air from the blower motor.

 

I need to update this post 1st. I have A350 economy line van
I found air is coming out the win Shield defrosters and no matter where I turn the switch the defroster air keeps coming out the only other posi on the switch that works is the off.it shuts the fan off, if the temp control is set on hot hot air comes out the Defrost vents if the temp control is
set on air conditioning the air out of the defrost vents does not get cold and I do not hear the A/C kick in, it does sound like it is Electrical.
and Probably a small fortune to fix. I am eighty seven years old and it's hard for me to get around

 

It's hard to follow your descriptions and you omitted the van's year.

If air only comes out the defrost vents, you have lost vacuum control to your vacuum motors in your dash located heat box. The system is designed to default to defrost. I feel you lost vacuum source feeding your heater box.which is preventing your blend doors from moving.

This could be a second issue but is also worth checking. It wouldn't hurt to make sure your compressor is running when in the a/c mode. A low refridgerant charge would prevent the compressor clutch from engaging or would cycle frequently. This would not cause a blend door malfunction.

 

In addition to posting the year, also tell us if it is a 4x4.

 

Thank you for all your help. I found my problem, the line from The manifold was leaking. YouTube had a bunch of repairs And I wasn't sure about the line that went to the check valve and the vacuum Reservoir So most of the repairs on youtube showed them bypassing the reservoir. I think I'll try this however they say when I stepped down on the gas pedal. I will lose vacuum. And it can kick over to the Defrost until it gets Vacuum .
not shore this is a big problem, the line to the check valve is almost Impossible to get to.. Again thanks for your help in getting me on the right track.

 

It's something you want to fix as that leak will such air and lean out your air/fuel mix.You don't want to bypass the reservoir. Your HVAC and vacuum solenoids will never work correctly. Do it right and do it once.