resurrecting 1996 Legacy 2.2L - what's this vacuum hose

[kite]

First post, new to Subarus. I've found some useful info here already, thanks!

I'm resurrecting a 1996 Legacy 2.2L that was sitting for most of the last decade in my wife's grandma's garage. I've got it running and driving seemingly as it should, with only two known issues at the moment. 

1) rodent chewed vacuum hose (I think), what is it? It hissed with vacuum when running. see pic

2) AC not working. The dash button doesn't light up when pressed. I don't have a full grasp of the system yet, most of my knowledge is from this thread. Here's what I've learned:

• Fuses:
  • 10A Fuse in engine compartment good. 12V is delivered to AC relay
  • can’t find second fuse that is supposedly in the interior fuse box, don't see anything related to heat or AC
• AC relay functions
• AC compressor spins when the relay is jumped
  • Air does not get cold.
  • I ran the compressor for longer than I should have if there’s no refrigerant, something I subsequently learned. oops
• dual pressure sensor switch on the drier is open circuit 
  • conclusion Faulty dual pressure sensor switch or refrigerant quantity insufficient”
  • Makes sense that refrigerant is low because it didn’t blow cold when i ran the compressor for a while
     

but since the light on the dash doesn't turn on, is there another problem also? or is there a string of sensors/switches in series, which must all be closed in order to power that dash light?

Thanks for the help!