I wasn't sure where to put this. Interior seemed most appropriate.

I just finished an engine swap and now air only blows out of the defrost vents (ones at the windshield) regardless of where the **** is turned. Ideas on how to get the air back through the vents in front of the dash?

Thanks.

 

Check the vacuum line.

 

The default operation in a vacuum leak is to blow thru the defroster only. As was mentioned, check your vacuum lines for proper connection and check for leaks.

 

Yah I figured it was probly something like that. Which vaccuum lines (location)?

Thank you.

 

There should be an underhood label telling you all the vacuum line routing. I'm pretty sure the vac line going into the firewall harness (on pass side next to dist) is the one, usually gets old and cracks. Also listen to the selector sliders and listen to hear if there's a hiss, there's a little round thing with 4 lines connected, sometimes they go bad and leak causing as mentioned above, "default defrost".Had same problem both my line and the selector was bad.

 

it is the line right behind the distributor it goes into the firewall right by the heater box not sure where the other end goes to prob vacuum canister.

 

The bold part is a very common problem. There are two valves (parts 3 & 12) in the HVAC controls. They're held together with plastic clips that break with age. When they break the valve leaks.

 

i'm pretty sure this is the problem i'm looking at right now. when the HVAC system is turned on i hear a hissing sound that seems to be coming from the control unit and i can only get a tiny amount of air coming from the defroster. is it possible to just get the clips replaced or do you have to get a whole new control unit? if possible what are the part numbers/link to buy?

 

Well now the defrost vents aren't even blowing. My fan isn't coming on at all. Regardless of position and my hot-cold selector is stuck on cold. I'm not sure if this is related to a small fire on the passenger side of the car, but I didn't see any wires burnt. The car's physically almost ready to drive, but now I can't because I can't see out my windshield. haha. I'd take defrost back if I could get it.

 

Is there any way that picture can be fixed? I'm also having the same "default defrost" problem and i cant find these plastic clips

 

Not sure if it will help but you can check this anyway, wont hurt.

A few weeks ago i replaced my heater core and removed the cover that goes on top of it on the passenger side, and when i would turn my AC on no air would come out of the Vents. I had to put the cover back on so that the air would re route itself to the vents themselves.

Make sure u didn't remove the cover

Good luck

 

Ignore my last post, for some reason I can view the picture on my phone, but not on my laptop, lol.... I also figured out that I had a vacuum line running to my egr valve, instead of to the back of the intake plenum

 

I have the same problem. I am curious at where the vacume line originates from. A lot of us bought our cars with swapped motors where th PO did not hook them up.

 

yah. maybe a vaccum line explanation? and where exactly does the system get power from? did it have to be run through the computer? as i don't think mine is functioning anymore. I checked the fuse, replaced it, but nothing. it doesn't even sound like it's trying to turn on. so where should i check for power?