A/C only coming out of defroster
#1
Newbie
Thread Starter
A/C only coming out of defroster
Hey guys, I'm having some AC/heat issues. Air is only coming out of the defroster. I've read that this is the default position when there is no vacuum to direct the air. I checked the vacuum lines in the engine bay and they all look to be in really good shape. My question is, what should be my next step. I live in phoenix and we're gonna be in the teens all next week so I need to figure this out soon. Do I need the take the dash apart? Is it a simple fix that I overlooked? Please help me out so I don't die of a heat stroke haha.
#3
Senior Member
Looks can be deceiving. The vacuum line originates at the intake then follow it back and if necessary physically check it for vacuum. It terminates at the vacuum reservoir which is behind the front right bumper. There are "t"s where the heater hoses go through the firewall (that one gets brittle) and at the cruise control on the front right inner fender (inside the hood) if yours has cruise. Also give a year and maybe we can get more specific.
#4
Newbie
Thread Starter
Looks can be deceiving. The vacuum line originates at the intake then follow it back and if necessary physically check it for vacuum. It terminates at the vacuum reservoir which is behind the front right bumper. There are "t"s where the heater hoses go through the firewall (that one gets brittle) and at the cruise control on the front right inner fender (inside the hood) if yours has cruise. Also give a year and maybe we can get more specific.
#5
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Year: 1990
Model: Cherokee (XJ)
Engine: 4.0
#7
CF Veteran
On my 1990, same symptom. cause was that the vacuum line got kicked off the servo motor for the air control flaps. this line and servo motor are in the passenger front foot well. my xj is missing the cover that protects this servo motor, so the it got kicked and the line fell off. check the foot well.
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#8
Newbie
Thread Starter
this is the part that is broken that I can't find a picture of. I do have cruise control and it's not working either. Is this part the solution to the problem or is it unrelated. I traced the vacuum lines through this part too.
#9
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Year: 1990
Model: Cherokee (XJ)
Engine: 4.0
Any leak in the system will give you both issues. Fix every one you see. The reservoir ball can also be cracked.
#10
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#11
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Year: 1990
Model: Cherokee (XJ)
Engine: 4.0
Most of this system can be repaired with standard vacuum line and plastic piping.
#12
Newbie
Thread Starter
sorry if it wasn't clear in the pictures, but, the big black piece has a nipple that has broken off. you can see that one of the tube ends is dangling off to the side. do you know which part that big black piece is?
#13
CF Veteran
Trace the output shaft of that actuator see where it goes. If its the throttle then its cruise control...it might go into the dash to control the blend doors.. i dont know renix configs but either way thats your problem. The broken off nipple in the black hose is a hole letting all your vacuum escape. You need to pry it out and get a plug at the auto parts store or do a really good job of sealing the end with electrical tape.. that actuator will no longer work .you probably can't repair the broken nipple
#14
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Year: 1988
Model: Cherokee (XJ)
Engine: 4.0L
Yes, that's the cruise control servo. It's vacuum actuated. That's the vacuum supply that broke off. Look below the servo to see if the line is still there, then plug it. You CC won't work, but perhaps your AC will.
#15
Newbie
Thread Starter
How would I plug the hole without making it permanent? The guy above said I could get a plug at an auto parts store, would that be permanent? I know it's probably a shot in the dark but I would like to eventually try and fix the nipple to get my cc to work (it's pretty nice on road trips). I tried epoxying the nipple back on and lost in the engine bay which really sucked haha.