HVAC Vacuum Leak Question

MnKMcNeilly

MnKMcNeilly

New member
Hey all,
New to the Jeeping (again). I have a 2005 Wrangler with the 4.0. I’ve done some research and found that my AC only blowing out of my defrost is a result of a vacuum leak. There is no obvious leak and changing out the switches didn’t solve anything (the blower resister was bad too and I changed it, but before changing it, I swapped the switches hoping to fix both issues. I’ll be sending the switches back). What is the best way to find the vacuum leak? Is there a good trick to find the leak? Is there a tool that I should buy?
Thank you!
 
MnKMcNeilly said:
Hey all,
New to the Jeeping (again). I have a 2005 Wrangler with the 4.0. I’ve done some research and found that my AC only blowing out of my defrost is a result of a vacuum leak. There is no obvious leak and changing out the switches didn’t solve anything (the blower resister was bad too and I changed it, but before changing it, I swapped the switches hoping to fix both issues. I’ll be sending the switches back). What is the best way to find the vacuum leak? Is there a good trick to find the leak? Is there a tool that I should buy?
Thank you!
Click to expand...
Old school trick was misting carb cleaner or either around all of the vacuum lines & listen for the idle speed to increase…

May not work with the most modern vehicles but maybe the TJ Is simple enough for that trick
 
CalSgt said:
Old school trick was misting carb cleaner or either around all of the vacuum lines & listen for the idle speed to increase…

May not work with the most modern vehicles but maybe the TJ Is simple enough for that trick
Click to expand...
Good trick. Works indeed.
 
^that works great in the engine bay, I doubt it'll have the same effect on the tiny vac tubes in the dash that hook to the selector switch and actuators. Oviously check for vac leak in engine bay first you can trace the tube from the firewall. Im assuming both heat and AC the only vent setting it comes out is the defrost regardless of switch selection? The only real way is to get in there and find it. You can use a vaccum tester on each of the lines off the switch, something like this, you can grab one at harbor freight or somewhere local for cheap too.

 
The other option would be a smoke machine but I don't recall ever seeing one of those for a decent price.
 
Thank you all! I may try the carb cleaner trick first (since I already have it), but very much appreciate the Amazon link to the vacuum pump. I will pursue that next.

if anyone else has experience or tricks with the HVAC lines, please feel free to add some more knowledge.
 
If you trace the vacuum line from the T along the firewall over to the battery tray, look to see if the line disconnected from the vacuum reservoir. You will need to remove the battery to see.
 
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