AC Center Vent Hissing Even When Car Turned OFF
I got a refrigerant recharge because the AC was not working -- blowing warm air and the compressor was not even engaging because I was almost all out of R134a.
I took it to a mechanic and the machine showed I had only 50g of R134a in the system. So the mechanic filled it with the specified 740g of R134a and the AC worked great at the shop.
Immediately afterwards, I hear constant hissing from the center vents, even when the car is turned completely OFF.
Any ideas why I am getting this hissing sound EVEN when the car's ignition is OFF?
Thanks