Wasn't sure where to post this, but since it's under the hood, I posted here.

There is a hard plastic tube routed under the battery box, through the firewall. Can someone tell me what it is? Pneumatic? Vacuum?

I noticed that my battery was leaking some acid down into the battery box. Caught it early enough to clean it up before any serious damage was done, but the acid did eat a pinhole into the tube. I was able to splice it with a piece of vacuum hose, but I'm curious as to what it is for? The doors all locked fine. Maybe a control hose for the ventilation routing system?

 

It may be the tube that pulls air from the passenger footwell into the black box located adjacent to the battery. There's a small fan located inside the right lower side of the box. It pulls cool air into the box to help reduce the temperature of circuit boards located inside.

 

Theres a tube that cools the box of electronics where the CPU is located and a tube that runs to the amp for the radio.

 

This tube doesn't go into the CPU box....it follows the wiring harness on up under the cowl in the center. Guess I'll just have to wait until something starts malfunctioning.

 

I saw the same thing when I changed out my battery last week. Where the tube terminated on the firewall there were several options(to connect the tube)I will be pulling the battery out tomorrow as I want to install a 3/8 plastic drain from the battery vent. The tube went to something that looked like the rear of a rotary switch. Will post findings

 

Exactly! Following it the other way, it goes under the CPU box and follows the wiring harness up under the cowl in the center. Had it not been getting dark on me, I would have investigated a little further.

 

Dan is this line a gray 3/16 or 1/4 inch O.D. hard plastic line you are talking about? If it is I looked at mine and this line runs to my engine up under the engine cover. I didn't look any further than this but I would think its a vacuum line.