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jeep_doral 04-30-2011 09:00 PM

A/C low pressure passenger side with new blend doors

I replaced my blend doors today after having almost no air blowing from the passenger side. Just as expected, the right door was broken. Replaced with new doors, checked everything was working as it should, assembled and only to find that the passenger side A/C is still not blowing as the driver side, about 80% less.

Can the vents be blocked by something? I'm I missing a filter somewhere?

Suggestions greatly appreciated.

1999 Jeep GC Limited

Frango100 04-30-2011 09:29 PM

Re: A/C low pressure passenger side with new blend doors
When you had the system open, did you check the ducts as far as possible for any restrictions or debris? Are the air outlets completely open on the passengers side? If you close the outlets on the drivers side, do you have a lot of air on the passengers side? Makes it any difference selecting high or low temperature?
Regarding the blend doors, they only redirect the air over the heater core or not. If temperature selection would make a big difference in air flow, then there should be some restriction in the heater core.

jeep_doral 04-30-2011 10:33 PM

Re: A/C low pressure passenger side with new blend doors
Hi Frank,

Closing the driver side outlets makes no difference in pressure. The center outlets right below the radio, left side has full air, right side almost no air blowing. I just can't figure a vent door or something that can make air vent to one side and not the other.

jeep_doral 04-30-2011 10:34 PM

Re: A/C low pressure passenger side with new blend doors
Forgot to add, temperature has no impact on the air output from the outlets, heat or cold, same volume of air.

Frango100 05-01-2011 07:50 AM

Re: A/C low pressure passenger side with new blend doors
When you close the vents on the drivers side, does the fan make a different sound, as if the air canīt go anywhere? If it doesnīt change, then there must be air escaping somewhere. Did you feel for airleaks in the passenger footwell area. If the airflow on the pax side doesnīt increase when closing the drivers side outlets, then there must be any kind of restriction in the pax side ducts.
Iīve heard problems before of uneven airflow and i think they are never exactly the same, but 80/20 is quite a difference. The only doors different for drivers side and pax side are the blend doors. Did you calibrate the doors to be sure that they go full open and full close? The other doors in the system are the mode door and the recirculation door, but they are common for drivers side and pax side.

Me Fix 05-01-2011 11:07 AM

Re: A/C low pressure passenger side with new blend doors
What fix did you do? Did you cut the box open from the front and install both doors tied together or did you do the Pro fix and take the dash and duct out so that you could install both doors seperate.

I bought my 2004 Overland used and I have error codes 52 and 56 although per Frank I was able to clear code 56, but still have 52. I may be in for fixing my doors soon. I'd rather fix them at my convenence rather than being on a trip and having problems then. I have read where some have the "cabin filter" which filters the incoming air. That would not effect the one side though, but if you have it and didn't know it, it could actually come apart and become part of a blockage that would effect one side or the other.

jeep_doral 05-01-2011 03:26 PM

Re: A/C low pressure passenger side with new blend doors
I did the "easy" and economical fix. Bought the blend doors and installed them myself by cutting the box. Not going to pay $$$ to have this fixed, it only cost me $100+ and the pleassure of doing it myself.

I did install the cabin filter a few months ago, I added it, was not part of the car. I can't see where it would block half side of the vents, but will give it a try.

I haven't tested any changes on the defrost or other air outputs, will try that as well. Some research I did this morning on the web calls mentions that the vacuum might be not working properly, it's an inexpensive part so I guess I'll just exchange it to clear that.

Will update any results after removing the cabin filter.

Thank you for all your comments.

Frango100 05-01-2011 06:07 PM

Re: A/C low pressure passenger side with new blend doors
With the AZC airco system, no vacuum actuators are used, it only has electrical actuators. So what should be the problem with vacuum?

Blen Dor 05-02-2011 08:17 AM

Re: A/C low pressure passenger side with new blend doors
Hello Jeep Doral:

The first thing you should do to diagnose the HVAC system is to read the fault codes.

That would be a good place to start your heater diagnostics.

To read the fault codes:
1. Turn on the ignition switch.
2. Turn on the AZC system. The temperature settings should be displayed for both sides.
3. Simultaneously hold down the AC and the Re-Circ buttons.
4. Then turn the driver’s side temperature (Left) control knob to the right (CW) one click.
5. Then release the AC and Re-Circ buttons.

If there are no fault codes, the “00” display value will remain in the window.
If there are any codes, each will be displayed for one second in ascending numerical sequence (note: no effort is made to display faults in the order they occurred). The left side set temperature display will be blanked and the right side set temperature display will indicate current and historical codes (8 historical max) presently active.
Once all codes have been displayed, the system will repeat the fault code numbers. This will continue until the left side set temperature control is moved at least one detent position in either direction, by pressing both the A/C and Recirc buttons at the same time, or the ignition is turned off.

Maybe the fault codes will direct you to the problem.

Post your fault codes, if you need help interpreting the code numbers.

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