So my heater has never worked, so today I turned it on full and opened the hood and i could hear air sucking in through this hole in the middle of the photo. Whats supposed to be there? Also, the thing just below it is for air conditioning im guessing?
 

Mine has a/c lines running through those holes.
 
As for the heater, have you got some rubber hoses and heater tap in the middle of the firewall?

Thanks heaps.. Just need to fill in the hole now.

Missed the second half of that message, was in hospital all night and worked all day so fair tired haha.. Yeah, I noticed that the white plastic notch was off it today too, so I put that back on, pretty sure that also had something to do with it.

Okay, so my heater doesn't work because the the two pipes that that go into the engine bay to connect to the engine are missing and are connected together with one hose. So first thing is to get the hoses. But I don't see why someone would go to the effort of blocking it for no reason so maybe the heater core is leaking I'm thinking.

How can I tell if its leaking without actually connecting the hoses and getting water everywhere then having to disconnect them again?

You really need to hook them up to get the water to flow properly.
I would be thinking its the hard lines that are above the fuel tank that would be leaking

Is that common? Damn that would be a major pain if it is for me. Especially considering the fuel pump just got replaced.

Yeah fairly common 

Thanks for the tip.

i bypassed those hardlines, and temporarily tapped into the coolant hardlines via the connecting silicone hoses underneath/behind the firewall for my heating. like evryone said those hardlines are common problem as of mine but i plan on fixing that the same time i upgrade my fuel pump to hit 2 birds with one stone