Vacuum leak?
 

I am having the typical problem of the air not blowing out of the normal vents, just out of the defrost vents. I had this problem before, found the leak, fixed it. Now a year later it happened again, this time i cannot figure it out. I have vaccume when i pull one of the caps on the system to check for vaccume, i went through every hose that i could find, and i checked the canister. Where is the mystical problem?
any input would be greatly appreciated

Dash selector. ↓

Sorry, i dont follow

Is there vacuum present at firewall connection to dash for Ac vent selector

I will check that tomorrow, is there a point to check that inside the vehicle to do i check in the engine bay at the firewall

Ok, so i finally had a few days to go through everything.

There is vacuum at where it goes into the firewall. all my hoses in the engine bay are perfect, i did a suction test on every section and did a test of the vaccum canister.

I have the dash halfway apart to try and find that line that runs though the firewall, but where the heck does it run too? i dont feel like taking apart litterally all of the dash to try and find that one little line. Is there anything else it could be?

:brickwall::brickwall::brickwall:

I also just learned that this could be a problem, there is a hissing sound when i turn off the car, sounds like its from the radiator area, passenger side... idk what it is but its probably has to do with my ac system cause i had problems with it cycling on and off all the time so i think there is a leak in it somewhere, but that should not cause my vents to screw up should it?

When you say you checked the canister, did you mean the vacuum ball down behind the right front bumper?

I also just replaced that little check valve coming off the intake mani, no luck with that one

Yes, i actually bought a new one just in case, but the one i had was fine

If i suck or blow on the vaccum line that runs into the cab there is no sign of it having a crack in it or a leak anywhere, it holds the suction perfectly.

OK...Sometimes that's called the ball, or reservoir, then there is the evap canister.

Then that hiss was in the neighborhood. (rad overflow tube?)

Sorry, I'm no real help. IIRC on my 90 it's not to tough to access the controls there if I wanted to check a valve.

My old thing idles at around 17in Vac Btw.

Im not sure where the controls are, and i cant find a write up on it.

I have the dash apart to the point where i have to take out the air bag, but to do that i litterally have to rip out everything else, so im waiting to see if there is anything i am missing

It's been 10 years, and waz on my 90. Changing the Radio, the controls are right under it. IIRC there are vacuum valves there. Maybe bump your post later for someone better informed than me! I just wanted to make sure you had the "ball" covered. Do be careful around that airbag. (I don't have one). Some can "go" when there is no power.....


In case you didn't happen to know, "advanced search" homes in a bit better than regular Google, hope this helps!> http://www.google.com/advanced_search?hl=en

Easiest way is but a pump with a gauge. Hook up each line one at a time. Pump up to 15-20 and let sit a few minutes. If it holds, no leaks.

Sorry but you sucking and blowing on a line is doing nothing. I would spend $30 on pump, before tearing dash apart.