[Johnnyboy]

    Need help, anyone know what this valve does, and should it have a hose hooked up to the bottom barb.

I noticed it was leaking air when I turned key on and  my dash heating controls, what was weird was my supply tank was empty until I turned on heater controls, once on the supply tank filled with 65 lbs of air and I noticed My left side airbags deflated. I assume the airbags filled my supply tank. Any thoughts. Thanks