location of a vaccum line

I was trying to find out where the vaccum tube that comes off the top of the heater control valve goes to. Mine looks like it laid on the top of the engine compartment and melted . So now i just have about 4 inches of tubing coming off the valve, but dont know where the other end should go once I replace it.   Thanks for any help

Since '73s didn't have the heater control valve, I'm just guessing here but I'll bet it goes to the control head in the console.  That's where the the other HVAC vacuum lines are controlled.  Someone here with a newer model may have a better answer.

Well, I thought I could help you out.  My vacuum line that comes off the top of my heater control valve on my 79 just hangs down in the engine compartment.  Not sure where it should go.  Sorry.

If it's the stock plastic tubing it comes out of the firewall near the distributor, kinda' high near the cowl, comes out of a grommet by itself. From there it go's into the cabin under the dash.