Air vent help needed

[Zinnal]

When turning on the fan, AC, or heater, the air really only blows out the bottom vents by the feet no matter which position I put it in, there’s a little bit of air that comes out the top vents, but not much…

Has anyone had this problem and fixed it? If so, what was the solution, I am wondering if there’s a switch that’s not working behind the dash 


 

[reddvltj]

When turning on the fan, AC, or heater, the air really only blows out the bottom vents by the feet no matter which position I put it in, there’s a little bit of air that comes out the top vents, but not much…

Has anyone had this problem and fixed it? If so, what was the solution, I am wondering if there’s a switch that’s not working behind the dash 


I would start by pulling the control panel and inspecting the wiring and the vacuum plug in. Your vent doors are all controlled by the vacuum switch. If you don't find any issue there Check to make sure the supply line for that switch is hooked up in the engine compartment.

Also check both ends of this connector.

 

[KennethS]

That’s the classic symptom of vacuum loss. Check the vacuum hose from the intake to the vacuum reservoir under the hood. That hose often gets disconnected or cracks due to age.

 

[Zinnal]

That’s the classic symptom of vacuum loss. Check the vacuum hose from the intake to the vacuum reservoir under the hood. That hose often gets disconnected or cracks due to age.

Thanks I will take a look tomorrow in better light. That is probably the case but I can’t find and disconnect or cracks currently by sight

 

[TheBoogieman]

Pull the knobs and make sure they're not cracked too.

 

[NskLJ]

That’s the classic symptom of vacuum loss. Check the vacuum hose from the intake to the vacuum reservoir under the hood. That hose often gets disconnected or cracks due to age.

Vacuum loss will default to defrost, it is a safety feature.

 

[NskLJ]

When turning on the fan, AC, or heater, the air really only blows out the bottom vents by the feet no matter which position I put it in, there’s a little bit of air that comes out the top vents, but not much…

Has anyone had this problem and fixed it? If so, what was the solution, I am wondering if there’s a switch that’s not working behind the dash 


Here is a vacuum diagram for the a/c heating system. The black means vacuum is applied. The best tool for this diagnosis is a hand vacuum pump where you can pump up each vacuum motor and verify no leaks. In your case I would look to a switch or a door binding. Verify the knob isn’t cracked and the switch is actually turning. Test each mode to see exactly what it is doing. The vacuum switch will apply vacuum to the actuators depending on the mode selected. As you switch modes you should hear a slight vacuum leak this is normal. It is releasing vacuum from the actuators. Pull the control head and disconnect the vacuum harness, it should go to defrost. If not check the actuators and arms ( refer to vacuum diagram and section 24 in service manual) if the floor door is stuck in the on position. Disconnect the actuator and see if the door moves freely if not you may have a physical restriction in the box. Be careful with the door arms you don’t want to break one.

https://www.amazon.com/dp/B073CNGMRG/?tag=wranglerorg-20

 

[sertshark]

I'm just gonna tell you guys, check the knobs FIRST. I assumed they were ok, because I could hear the air in the system switching as I turned the dial. I traced all the hoses, pulled out the battery tray, checked here, and there, and everywhere... Until I pulled the knob off, and it looked identical to the one Boogeyman posted. I switched it with a knob that wasn't cracked, and holy **** air started coming out of the vents.

 

[Moglocker]

Vacuum loss will default to defrost, it is a safety feature.

Wow I didn’t know this?