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-   -   Is this a A/C blend door problem? (http://www.jeepgarage.org/f203/is-this-a-a-c-blend-door-problem-10968.html)

JGrove 07-10-2010 01:07 PM

Is this a A/C blend door problem?
 
My 2003 Jeep GC's air will go in and out. When it goes out I'll just tap on or wiggle the heating/cooling knob and the cool air kicks back in. When it doesn't work it's not hot air that comes out. It's somewhat cool, but just not cool enough during the hot summer. When I wiggle or tap the knob it will sometimes keep working up to day or even over a week. The same problem happens in the winter when I need us the heater.

Is this the blend door, thermostat, blower motor or do I just need to get a new manual temperature control console? Thanks

Frango100 07-10-2010 10:26 PM

Re: Is this a A/C blend door problem?
 
It looks like that you have a problem with the blend door actuator. As long as you still have air blowing in all cases, the blower is ok. But when you dont get cold air during summer or hot air during winter operation, it looks that the blend door actuator is stuck somewhere half way. Im not familiar with the manual system, but when im not wrong you can access the blend door actuator by removing the glove box.

JeepMe 07-12-2010 09:09 AM

Re: Is this a A/C blend door problem?
 
Mine does almost the exact same thing. A/C will go from COLD to moderately cool and back to COLD at random. It also does the same thing for heat.

I've check the actuator to see if it's moving and it works fine from what I can see. The actuator is near the left side of the passenger footwell under the dash. It has a metal rod that turns with the temp control knob.

I have noticed that when the A/C (or heat) isn't working right, I can turn the temp knob to full hot and the temp stays the same moderate cool. For myself, what makes it hard to diagnose is that the problem is intermittent. While the Jeep is parked, the A/C always seems to work. The problem seems to randomly happen when driving so I can't check the actuator to see if it's moving when the problem happens.

I've come to the conclusion that it's either the acctuator not moving b/c of bumps or something or the blend door is broken. Since the actuator is $70 and the blend door fix is about $100, I'm going to look into it more before I make my decision.

JeepMe 07-15-2010 04:54 PM

Re: Is this a A/C blend door problem?
 
Finally had the A/C not work correct when I could pull over and check. Opened up the glove box to look at the actuator and it does NOT rotate when the temperature dial is moved.

I will conclude that this is either a problem with the actuator (like someone said) or a problem with the temperature control knob. I'll have to break out the DMM when I can get it to do it again and test. But, this is NOT a blend door problem (which is a good thing IMO).

Frango100 07-16-2010 03:17 PM

Re: Is this a A/C blend door problem?
 
Check the connector on the blend door actuator and also the one on the backside of the AC/heater control panel. Can be a bad connection or maybe an interrupted wire. When you say that it works for a while when you mesh with the temp switch, the problem can be inside the switch as well. I have never opened it, but it is probably a variable resistor inside the switch. Maybe some electrical cleaner on the switch could help.

Duffer 07-20-2010 07:46 AM

Re: Is this a A/C blend door problem?
 
I am extremely happy to have discovered this forum. I have the exact problem described by JeepMe where both the AC and Heater temperature fluctuates. I pulled the control panel out of the dash to see if I could spot any obvious problems, but didn't see anything. I put it all back together -- ensuring there were no loose connections -- and continued having the problems. So I guess

Duffer 07-20-2010 07:49 AM

Re: Is this a A/C blend door problem?
 
Sorry, hit enter too soon. I was about to say that I guess I need to start looking deeper into the actuator side of the AC/Heater. I have a picture of the temperature control device if anyone is interested is seeing what it looks like from the inside of the control panel.

Duffer 07-23-2010 06:05 AM

Re: Is this a A/C blend door problem?
 
While digging deeper into the problem, I had the rare opportunity to observe the malfunction while it occurred. I had dropped the glove box and removed the actuator from the blend door control. I confirmed that the blend door was functioning properly by manually rotating the blend door knob (I could hear/feel the blend door opening and closing as I turned it). So I started looking closer at the actuator itself... When I turned the temperature control to the cold position, the actuator rotated to the left as it was supposed to. When I turned the temperature control to the hot position, the actuator rotated properly to the right. I continued changing the temperature control and the actuator continued responding properly, but then all of a sudden, the actuator stopped responding altogether -- seemingly stuck at the midpoint position (halfway between cold and hot) -- and would not move when I rotated the temperature contol knob. At this point I was almost convinced that the actuator had died. But just for the heck of it, I tapped on the center of the temperature control knob and the actuator started responding!! So the only thing I could conclude is that I have a faulty temperature control, since everything else seems to be working properly. But now for the bad news... I went to my local jeep dealer to order a replacement temperature control and it was $130, which seems outrageous for such a simple control. But having no choice, I ordered the part and it is supposed to arrive today. I'll install it over the weekend and observe it closely for the next couple of weeks to verify that the problem has been resolved permanently. I'll post an update with the results for anyone that might be experiencing the same temperature fluctuation problem.

JeepMe 07-23-2010 10:47 AM

Re: Is this a A/C blend door problem?
 
Quote:

Originally Posted by Duffer (Post 240196)
While digging deeper into the problem, I had the rare opportunity to observe the malfunction while it occurred. I had dropped the glove box and removed the actuator from the blend door control. I confirmed that the blend door was functioning properly by manually rotating the blend door knob (I could hear/feel the blend door opening and closing as I turned it). So I started looking closer at the actuator itself... When I turned the temperature control to the cold position, the actuator rotated to the left as it was supposed to. When I turned the temperature control to the hot position, the actuator rotated properly to the right. I continued changing the temperature control and the actuator continued responding properly, but then all of a sudden, the actuator stopped responding altogether -- seemingly stuck at the midpoint position (halfway between cold and hot) -- and would not move when I rotated the temperature contol knob. At this point I was almost convinced that the actuator had died. But just for the heck of it, I tapped on the center of the temperature control knob and the actuator started responding!! So the only thing I could conclude is that I have a faulty temperature control, since everything else seems to be working properly. But now for the bad news... I went to my local jeep dealer to order a replacement temperature control and it was $130, which seems outrageous for such a simple control. But having no choice, I ordered the part and it is supposed to arrive today. I'll install it over the weekend and observe it closely for the next couple of weeks to verify that the problem has been resolved permanently. I'll post an update with the results for anyone that might be experiencing the same temperature fluctuation problem.

I also believe it's the temp control knob. Since the OP stated his starts working if he taps on the knob, I started trying it. While mine requires a rather strong tap, it does start working properly after that.
I'll have to check a junk yard and see if I can pull one from another Jeep b/c $130 seems REAL expensive. Keep us posted if that fixes the problem. If so, I'll be ordering it when I get back from work travel in 4 weeks.

Frango100 07-23-2010 03:24 PM

Re: Is this a A/C blend door problem?
 
You could try to use some electrical contact cleaner on the temp selector to see if that will make any difference. Could be a bad contact on the variable resistor.

Duffer 07-26-2010 10:53 AM

Re: Is this a A/C blend door problem?
 
I picked up the part from the Jeep dealer and now I know what it cost $130. Jeep requires you to purchase the entire Heater/AC control assembly (i.e. all three controls) and not just the temperature control. At any rate, I installed it and so far I haven't see a recurrence of the problem, but it's way too early to declare victory.

The junk yard option is an intriguing idea, but I'd be concerned that you might be purchasing someone else's (old) problem. If you decide to go this route, I'd be interested in the cost, as then I'll know how much of a premium I paid to go through the Jeep dealer. However, I have already rationalized it in my mind, as at least I didn't have to pay outrageous labor charges to make this simple part swap.

I have a long road trip planned for the middle of August, so I'll have an opportunity to monitor the temperature over an extended period of use. I'll report the results after I return.

JeepMe 07-26-2010 10:53 PM

Re: Is this a A/C blend door problem?
 
What was the part number?


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