'05 TJ A/C problem

[Oldchief]

Factory A/C in my '05 TJ cools OK but cool air only comes out of windshield defroster vents, no matter what setting I have the directional selector set on. What's most common cause of this problem? Thanks!

 

[greg92jeepxj]

The blend doors are not opening as you know but the cause will either be loss of vacuum or , and hopefully not , broken blend door actuator arm. Hard enough to get into the right position to just look up at the vacuum cylinders to verify if they work , but you will want to verify if they are actually operating and if anything is disconnected or broken. Look for the vacuum lines under the hood where the vacuum source originates from on the intake manifold where all vacuum lines are and see if any of the vacuum lines that go through the firewall cut , dry rotted , loose or damaged at any point. Good time to change any vacuum lines that may be bad as vacuum leaks affect engine performance. That vacuum source will lead to the dash control and knob selection will distribute what blend doors open and close. Hopefully it is just an issue with vacuum and nothing has broken . It will take a visual inspection however. You want to see if any of the linkage is moving when controls are selected. Since there is no distribution and air is blowing straight through through the main vents to defrost and lower dash , the blend doors are not closing off the defrost and lower vents for the face vents since the vacuum cylinders , called vacuum motors , are not receiving a vacuum signal from the control unit on dash. I own an XJ , but the vent system is not a great deal different , just easier to poke your head up and see what going on up there. Sorry about that. Wrangler bodies are a little shorter so the dash is more compact for more driver/passenger room and of no favor to a tech.
The only other item that may cause this is the vacuum switch in the dash control itself , which may be integral on later years unfortunately , separate on my '92. You did not say there is any hissing noise when knobs are selected , that should mean the dash control is ok , but vacuum source to dash control must be verified so as not to assume . Hope this helps . Greg

 

[Oldchief]

Greg,
Thanks for your very detailed reply. Will be under the hood & dash in the morning, with my flashlight!

 

[greg92jeepxj]

Your most welcome . Please don't throw your back out , will curse myself for writing this post. I know the feeling all too well .

 

[JPNinPA]

Check here first

 

[greg92jeepxj]

Check here first http://s825.photobucket.com/user/JPNinPA/media/TJVaclines.gif.html http://s825.photobucket.com/user/JPNinPA/media/VACLines.jpg.html

Your a prince ! Thank you sir.

 

[SteelHeadz]

And don't forget, there's a vacuum reservoir under the battery tray. Check the vacuum lines there too..

 

[greg92jeepxj]

And don't forget, there's a vacuum reservoir under the battery tray. Check the vacuum lines there too..

Yes , the tank that amplifies the vacuum signal for cruise control . Saps a lot of vacuum . Very important . Thank you sir !

 

[JPNinPA]

And don't forget, there's a vacuum reservoir under the battery tray. Check the vacuum lines there too..

The can is #8 in he diagram.

 

[Oldchief]

JPNinPA, thanks for the diagram and pic. Found problem this afternoon...vac line shown in pic, 3rd arrow from top was loose. Reconnected it and secured connection with a small zip tie. A/C vents are working perfectly now. Thanks for the help!!!

 

[JPNinPA]

Glad you got it fixed. That is the main vac line that is in the diagram. You might consider replacing the elbow as they often dry rot, crack and keep leaking. ddc4dddc4d

 

[greg92jeepxj]

I love happy endings . Thanks all ! :verry-happy: