blower motor work on all speed but very little comes out of vents
I just purchased a 2002 ford econoline and the a/c was not working very well so I added a can of 134a pressure on gauge is 45 psi the air coming out did get cooler but, I'm getting poor air flow, at 70 mph it helps.
Check your vents could be a mouse nest or other stuff.
You may have an issue with the damper door in your air handling plenum, usually a vacuum diaphragm will go bad or a vacuum line may have come off or be leaking.
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