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a/c blowing through defrost vents

G

garciaxj88

NAXJA Forum User
Location
yuma,arizona
Im not really fond of a/c systems. Found out air blows through the defrost vents. No matter which setting you put it on it still blows through the defrost vents. Im able to change the fan speeds and can change the temp aswell. Anybody deal with this issue?
 
Mine had same issue. 99. I found a random vacuum line front right corner behind the bumper. No idea where it goes. I plugged it up, and now my ac blows normal.
 
Passenger side, front, behind bumper. Also, start blower motor on low, then move to high setting if needed. On mine, if I start on high, it will only blow from defroster, until I switch it back to low, then to high it works fine.
 
i dont know about 99, but my 91 had a vac canister right behind the right front bumper. i took it off and plugged the line since it would have gotten ripped off wheeling. i bungee chord it on when i smog.
 
mako my day said:
Mine had same issue. 99. I found a random vacuum line front right corner behind the bumper. No idea where it goes. I plugged it up, and now my ac blows normal.
Click to expand...

It should attach to a vacuum bottle reservoir hidden in the bumper
 
:dunno: What year? It does make a difference.

Vacuum line loose, or leaking under the dash, in the dash AC/heat controls, or near the firewall where the AC and heater hoses attach, or a bad vacuum valve diaphragm under the dash that operates the doors.


garciaxj88 said:
Im not really fond of a/c systems. Found out air blows through the defrost vents. No matter which setting you put it on it still blows through the defrost vents. Im able to change the fan speeds and can change the temp aswell. Anybody deal with this issue?
Click to expand...
 
like I said earlier, search results:

ilhu92.jpg
 
The canister behind the passenger side of the front bumper is a vacuum accumulator that provides the vacuum needed to control the vents. The default is defrost when vacuum is lost. In addition to losing environmental controls, you also have a vacuum leak in the system, which will cause other problems. Just plugging the line will help, but you'll find that the vents will switch back to defrost under high acceleration because of the vacuum drop that happens when the throttle is opened. The accumulator is needed to maintain constant vacuum under all conditions.
 
Buy a cheap cigar, light it up, get a mouthful of smoke, blow it in to one end of any vac line. Watch for leaks (smoke escaping) up and down the line.
 
ParadiseXJ said:
Buy a cheap cigar, light it up, get a mouthful of smoke, blow it in to one end of any vac line. Watch for leaks (smoke escaping) up and down the line.
Click to expand...

???? A vacuum leak means outside air is being sucked in, not expelled. ????

Spray carb cleaner along all the lines and junctions. If there is a leak, the rpm's will change.
 
What's the best way to test any of the components that are shown in that picture?
Click to expand...

Unplug # 5 from the CC servo and with a hand vacuum pump draw the system down. It should hold vacuum, watch the gauge.

This will prove the check valve is good and that there are no leaks in the system.
 
I found that small vacuum leaks can be found by turning the engine off and listening, quickly!!!
 
old_man said:
???? A vacuum leak means outside air is being sucked in, not expelled. ????

Spray carb cleaner along all the lines and junctions. If there is a leak, the rpm's will change.
Click to expand...

...but this method finds the holes...and the carb cleaner method works fine on the engine side vacuum...not so much on the HVAC side.
 
sorry guys havent been able to get on lately. i found my problem concerning this issue short after i read your responses. i found the vaccum hose going to the intake manfold had come off somehow. idk how or when i possibly knocked if off but it happened. a/c now works just fine. thanks everybody for the help.
 
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