Heater and a/c vacuum lines
 

I have a 1980 chevy k30 with factory a/c bought the truck about a year ago and this vacuum line has been disconnected prior to me purchasing it can anyone tell me where it's supposed to plug in at as I have looked all over and can't locate where. Thanks

Re: Heater and a/c vacuum lines
 

You need one of those hoses to go through the firewall and connect to a round(ish) pint sized canister on the engine side of the firewall. That is where the system gets the vacuum to operate. The canister also needs a connection to manifold vacuum.

Re: Heater and a/c vacuum lines
 

Both lines are hooked up on the engine firewall side to the round canister.

Thanks

Re: Heater and a/c vacuum lines
 

Tagging for comments. My blend door on my 83 isn't working anymore after swapping in a new A/C control. I replaced the plastic bit that breaks with a billet clip while I had it apart so I know it's not that.