There is a clear PVC tube next to the battery (to the right, facing the windshield) that is disconnected. It's about 8-10mm in diameter. Anyone know what this is and what it connects to?

I'm wondering if it's a drain tube for the beauty cover that is missing from my engine bay.

 

I have the battery/brake reservoir cover on mine and there's no drains in it that i can see. Both ends of it are disconnected and its just laying in there?

 

Probably for a battery vent.

 

One end appears to be connected via the duct where the heater core hoses go into the engine compartment. I haven't traced where the hose starts, but the open end is a little flared like it was connected to something at one point. It's just hanging loose next to the battery.

 

Old school muscle car guys used to run tubes from the heater box to exterior-mounted tachs to keep them from fogging up, but i can't imagine why you would have one way over there that makes no sense. Sounds to me like some kind of DIY vent or drain.