What is bellows looking thing on passenger firewall

[gramps77]

There is a plastic bellows looking thing with a larger vacuum line going to the engine and a smaller vacuum hose going into the firewall just behind the A/C and heater box. What does it do and is it important to replace that smaller hose going into the firewall with similar plastic type hose?
I think it may have something to do with the defroster cause my defroster had stopped cycling on and then I found this smaller line with a large crack/break in it.

[jon75]

I believe the item you are talking about is the A/C accumulator vacuum ball. It acts like a cushion for the vacuum on your HVAC system. Essentially, as you drive, the vacuum produced by your engine fluctuates up and down with different driving conditions. But, as you know, the HVAC system operates a blend/mode door via a vacuum system.

I hope this information helps you with your defrost issue and helps to explain how it is important for you. Best of luck man!

[gramps77]

Originally Posted by jon75

I believe the item you are talking about is the A/C accumulator vacuum ball. It acts like a cushion for the vacuum on your HVAC system. Essentially, as you drive, the vacuum produced by your engine fluctuates up and down with different driving conditions. But, as you know, the HVAC system operates a blend/mode door via a vacuum system.

I hope this information helps you with your defrost issue and helps to explain how it is important for you. Best of luck man!

That makes sense. I'll try replacing the hose and see what happens.