jeepxj1997

Does anyone know why heat blows out my defrost but not my vents, just cold out. previous owner had it flushed 3 times and it never was glogged and there is no antifreeze on the passenger floor. Any ideas? also i replaced the u joints in the rear but still have a vibration. would a bent crossmeber thats is on the transfer case throw a diffrent pinion angle ans cause a vibration. i want a smooth ride. Any ideas???

Gee oh Dee

First off, welcome to our forum. I see this is your first post.

The heat issue could be a few things, the blend door is the first that comes to mind. If there is never any heat coming out the system, its probably stuck on cold. However, if there is indeed heat and its coming out of the defrost only, it could be a vacuum related issue, as the doors are switched by vacuum. When you use the fan does air come out anywhere besides the defrost, warm or cold?

Now, you have two problems in your thread, obviously having nothing to do with each other. Since the second issue you brought up isn't even in the title, I suggest creating another thread in OEM Tech with addressing your second issue.

Be sure to list everything about your vehicle such as year, motor, trans, and any lift or recent work that has been done or needs to get done.

Good luck.

JeepDeep

Just hope that when you get the vents working they don't blow black specs in your eyes! CONSTANTLY. I leave it on feet or defrost for that reason lol.

X2 on the vacuum. Check those lines.

DrShaggford

X3 on the vacuum lines. I have seen that they really like to snap/crack where the line goes through the header panel to the vacuum ball mounted on back of the passenger side bumper.

stoney0708

My jeep did this when I got it. Check vacuum line going by the battery goin to the vacuum canister.

jeepxj1997

thanks everyone for your info. and yes the fan blows cold air out the vents just warm air out the defrost. but they all blow air and really good. just cold air and like i said the heater core has been flushed 3 times.

Gee oh Dee

Its probably a vacuum issue.

CPLSeraphim

I've had the same issue, just not worked on it yet. I'll let you know if i get mine fixed. Your a local kid out in carlisle. Good luck.

idarland93

I’m having this issue also. Anyone know which line it is?

Brynjaminjones

Have a look at the side of your intake manifold. I know you have a 2.5, but on a 4.0 that's where the line connects. I've had one pop off before, which caused the vents to get stuck on defrost.

If you need more help, I'd suggest starting a new post as this one is 9 years old!

cruiser54

It's old, but he searched!!

Brynjaminjones

Absolutely! Just thought I'd get in with a friendly comment before the normal "Holy thread resurrection" comments

cruiser54

Much appreciated!!

EEVEE

Mine started doing this as well but after replacing the evap and heater core. got some sort of vacuum leak. mine specifically are in the actuators themselves. but firstly you can try to change the main vacuum supply going from the engine bay inside the cabin. that helped mine alot but alas didnt fix it 100%.