Johnthepanpire

Hello again everyone,

So I'm hoping to get my a/c recharged and I went to test it today and it would only blow from the defrost vents on the dash.
Blows nice and hard but only from those vents. Any suggestions?

macgyver35

This is a classic Jeep issue. This is almost always caused by a bad vacuum line or connection, or a cracked vacuum canister.

Behind the front bumper on the passenger side, there is a spherical vacuum canister about the size of a softball. These are prone to being hit by road debris and cracking, or just cracking over time due to heat and cold. Your problem is usually that the canister has cracked, or that the vacuum line going to it has cracked or come loose. Start at the canister and work your way back toward the firewall looking for cracks in the hose, especially at the connections, or any loose connections.

Johnthepanpire

I just went and looked and couldn't find it, do I have to take some stuff off to see it?

macgyver35

Sorry. Brain fart. Wasn't thinking about yours being a 90. Your may look more like the one below, and should be either behind the front bumper or behind the radiator cross member just in front of the motor.

monstercherokee

When I drive and hit about 60 it stops blowing from my vents and blows from defrost vents but when I slow down it goes back to the normal ones

macgyver35

Yep. Classic vacuum leak symptoms. Check for the same things I mentioned to the OP. Just sounds like your leak isn't as bad yet.

tgordon

+1

jomps

thought that was normal

now i know

Johnthepanpire

Ok I found it, it was behind a splash guard. The hoses coming off all looked ok, along with the connections, traced it all the way back to the firewall and everything looked/felt in like it's good condition EXCEPT one thing.

I thought it was for the heater core but maybe not.




See below the overflow tank, one missing house and one barely hanging on, could that be causing the problem??

Johnthepanpire

And I have no idea where the missing hose goes, if anywhere....

freegdr

one goes to vent control on dash the other goes to heater control valve .

freegdr

its in behing the plastic inner fender by horn pass side behind bumper

classic leaking check valve get a in line check valve install on vacuum line going to vacuum canister it will help greatly

Johnthepanpire

I took off the heater control valve because I have a cracked heater core and bypassed it so should I cap off one to the hcv?

Mobmoney33

So my ac wont blow through the front vents only my defrost, i am missing the vacuum line coming from the fire wall, any way i can get to blow from my front vents