Can y'all tell me where this vacuum line goes? It is a white-ish green line that comes out of the firewall on the passenger side, it is next to a black one, it was just blocked off. Thanks guys

 

It ll help if u had a picture and a little more info such as your year, model, and engine

 

Heater control valve.

Fill out your profile while you're at it, okay? Or, post your specs in the thread?

 

A vacuum leak causes your vent to default to defrost position. I'd guess the line you're looking at needs to have manifold vacuum. There should be a line on the pass side fender that goes thru your firewall and to a vacuum reservoir somewhere behind the front bumper. If you have cruise control, the line tees off near the servo.

 

He said "I have a 1990 jeep cherokee with a np231 tc."

 

Oh, did he? But decided to edit and delete it?

 

I'd be looking for the vacuum ball in the front bumper before anything else...

 

Go to his profile and look at his posts.

Not rocket science.

 

What would he do with it if he sees it?

 

Fertilize it.


JK...check the connections on it. First thing I thought of when I read "blocked off line" is that perhaps the previous owner removed it.

 

Waaaay too much work.. you must have too much time on your hands CC...lol

 

I can recall a recent thread on this...bomb vs egg...

 

Okay well I found that the previous owner took the heater control valve out and just plugged that line up, could that be causing my problem thanks guys.
1990 jeep cherokee laredo
4.0 aw4 269,XXX

 

No, it would not.

 

I had the same problem, I followed the vacuum line and it was cracked. As soon as I taped it up it blew cold air from the correct vents. It was cracked right under the battery!