Can anybody answer this question?? My a/c works but the air comes in and out of the vents and through the defrost. I put a vacuum reservoir in since it wasn't there. I guess they forgot to put it in when they switched engines in it. However it still doesn't seem to fix the problem. A/C runs cold but I have to mess with the power settings to get it to run through the vents when it goes through defrost. I'll put it on the lowest setting then switch to the highest and it seems to switch back to coming out of the vents. Any ideas?

I have a 98 4.0 automatic, 4x4

 

Vaxxum leak. Maybe hoses to resevoir on backwords or electrical issue.

 

i guess depending on where the leak is depends on how much a repair cost would be?

 

Yeah, pretty sure its a vacumm leak, if i were you, take a bottle of soap and water, spray it on the vacumm hoses to see where it is, if you cannot find it, look at the resistor, on mine it was rusted out and wouldnt work anymore, causing it to only blow out of the defroster.

 

there are two vacume lines going to a plastic ball, they are either unpluged or cracked

 

ok thanks geikoman, that was my next question; how to find where it is

 

the vaccum ball is on the passenger inner fender

 

yeah that vacuum ball is called the vacuum reservoir apparently thats what i was missing when they swapped out engines and forgot to put it in. i ordered it since it was a dealership item and connected the hoses to it and my problem didn't disappear