Xoferif

So, I've got one vacuum line that I have a few quick questions on...

There are two lines that come out of the firewall...one is for the heater controls and the other is for the heater valve...well, both of the lines coming out of the firewall are the same length as each other....yet the one should be able to run all the way to the heater valve, right?

So, I'll probably just end up running a hose from that to the valve then...but why would someone cut it in the first place? Just seems odd....also, how much vacuum should that line have? Because it hardly has any at all....more importantly, how important is that line? What does it do on the heater valve? Because my heater works just fine without it hooked up...

Thanks.