2KXJJEEP

NEED some help i have a 2002 WJ and my air only blows through the defrost vents no matter what setting I select...is there a fix for this...thanks

samurai

I had the same problem if you search there is quite alot of info on this,its a Vacuum leak,in my case it was a pipe had come off the inlet manifold,but in most cases it seems to be related to the vacuum reservoir which sits behind the bumper,when you get a vac leak the heater controls go to default setting which is screen only...

Bustedback

The vacuum reservoir is under the battery tray on a Grand Cherokee.

2KXJJEEP

iv checked the vacuum lines on the manifold and the blend door actuator both r fine. How do u check and see if the vacuum reservoir is working?

Bustedback

It's just a sealed container with a nipple or two. Look for cracks, or if the hose is even connected. No moving parts.

2KXJJEEP

i have check all the vacuum line that r under the hood now where do i go from here

Bustedback

Look under the battery tray.

2KXJJEEP

checked under the battery tray and everything looks good

jiris248

Not exactly true. An important part of the system is a non-return valve (usually located close to the manifold, sometimes on the inlet to the vac canister). If malfunctioning (happened to me), all vacuum operated systems will work well on idle, but will start plying up as soon as you step on the accelerator.

2KXJJEEP

what is tha thing on the driver side floor board up to the right of the gas paddle

CrazyMacaw

I think you're referring to the side of the heat/ac housing.
It contains the blower fan, heater core, a/c evaporator, blend and vent doors, actuators, and some duct work stuff.

2KXJJEEP

well i must be some type of vent doors actuators bc i can move it be hand and it will change it to the vents or floor.