Climate control question

Mclovin

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Joined
Oct 20, 2022
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19
Location
Auburn, AL
I have an issue with my climate controls in my 2001 TJ. I tried searching and have not found the same issue, so I am asking for help. All of the sudden the symptoms are

Only the lowest selection on the blower knob works. Every other election results in zero airflow.
The air vent selector knob works in the off position, anny other selection results in defrost air. At the previously mentioned low setting.

The second issue sounds like a vacuum leak somewhere. But combined with the first issue I wonder if it’s the controller. I pulled the knobs and made sure they were moving the selectors.

Cobey
 
When it's on the other settings, is the blower blowing but no air is coming out?
 
When it's on the other settings, is the blower blowing but no air is coming out?

Air comes out of the defroster in all location settings. But it will only blow on the lowest blower setting. If that makes sense.
Aka low and feet blows out the defroster. High and feet is no air anywhere.
 
Air comes out of the defroster in all location settings. But it will only blow on the lowest blower setting. If that makes sense.
Aka low and feet blows out the defroster. High and feet is no air anywhere.

It sounds like you might be dealing with a couple of issues. Based on your what you've described, it does seem like a vacuum leak could be affecting the air vent selector, causing all airflow to default to the defrost. The fact that you only have blower operation at the lowest setting is likely a separate issue, potentially related to the blower motor resistor.

Here are a few steps I'd suggest:

Check for Vacuum Leaks: Inspect the vacuum lines under the dashboard and in the engine bay. Look for any disconnected or damaged lines that could be affecting the actuator for the air vent selector.

Blower Motor Resistor: The blower motor resistor is a common issue in TJs. If you're only getting low speed, it's possible that the resistor is faulty. You might want to check the connections and replace the resistor if necessary.

Blower Motor: If the blower motor is only working at the lowest setting, it could also be on its way out. You might want to consider testing the motor to see if it responds at higher speeds when powered directly from a battery.

Control Module: If both the blower resistor and vacuum leak check out, you may want to look into the climate control head itself to ensure that it's functioning properly.

Let us know what you find!
 
Sounds like a great plan of action for this weekend. I find it hard to believe that both things happened at the same time so I am leaning towards the control panel, but it’s worth checking everything else.
 
Sounds like a great plan of action for this weekend. I find it hard to believe that both things happened at the same time so I am leaning towards the control panel, but it’s worth checking everything else.

Not the control panel. The stuck in defrost is no vacuum to the control. 95% of the time it will be in the engine compartment. There is a black plastic line with a one way check valve in it coming from the manifold to the firewall right by where the heater hoses connect to the heater core. The line will tee off down to a vacuum reservoir (black plastic box under battery tray) check this line for cracks. You can replace with regular vacuum line or repair with small rubber hose (3/32” I think) I like to hit the line with brake cleaner or a drop of super glue before slipping the hose over the line to glue it on.
The blower is most likely the resistor but I would check the switch wiring for melted connections. If so replace motor also.
 
So some more info. The cruise control works perfectly. I see a lot of people saying a vacuum issue will make the cruise not work.

Second, as I was messing with it, I can get the blower to blow high. But the switch selector needs to be wiggled between detents. Can find just the right spot to get the blower to speed up.

I don’t see any cracks in the engine compartment lines.

I will keep troubleshooting

Cobey
 
So some more info. The cruise control works perfectly. I see a lot of people saying a vacuum issue will make the cruise not work.

Second, as I was messing with it, I can get the blower to blow high. But the switch selector needs to be wiggled between detents. Can find just the right spot to get the blower to speed up.

I don’t see any cracks in the engine compartment lines.

I will keep troubleshooting

Cobey

Crawl underneath and make sure the hose is connected to the reservoir underneath the battery tray
 
Crawl underneath and make sure the hose is connected to the reservoir underneath the battery tray

I am also having the problem being stuck in defrost mode. I changed the head, found the leak at the box under the battery and still no change
 
I am also having the problem being stuck in defrost mode. I changed the head, found the leak at the box under the battery and still no change

Check the plastic lines running from the intake to the firewall. Run you hand along it to feel for leaks also check right at the firewall.
 
I haven't been able to feel anything. Trying to get my hands on a smoker

Check to see if you have vacuum at the control head, if you do not you have a supply line issue. If you have vacuum check the hoses to the vacuum actuators under the dash. A vacuum pump would be more useful than a smoker. You can go to the control head and check each circuit to make sure it’s working then you can pump down the vacuum reservoir to verify no leaks. You can seal the vacuum supply line and pump it down for leaks.
https://www.harborfreight.com/brake...MI4_Xv1_7ajgMVSp7uAR160AHtEAQYBCABEgJG8_D_BwE
 
So I picked up a smoke machine and my leak is at the plug that plugs into the head. I've tried to purchase a new harness, but can only find them 12" long and mine is 18" long. Any advise as to where i can find a longerbone?