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-   -   Low vent air pressure (http://www.jeepgarage.org/f203/low-vent-air-pressure-26230.html)

D-Money 07-25-2011 03:24 PM

Low vent air pressure
 
Hi i was wondering if anyone else has had this problem. Over the winter i had my heat fixed, I'm not sure of everything that was done, but i know i had a heater core and exchanger put in. Then this spring i had my a/c recharged and on a 100+ degree day my blower? started acting up. The air struggled to come on, and I'm not talkin cold I'm mean any air, but after a while it was fine. Now when i turn the air on it blows ice cold and the heat warm, but as far as pressure it equal to exhaling normally into your palm and it only blows when i am driving and have my foot on the accelerator. I am asking because i can't afford to pay the stealership $135 an hour for an "Exploratory Diagnostic".

Frango100 07-25-2011 03:59 PM

Re: Low vent air pressure
 
Sounds that your blower is not working. Check first the connectors on the blower motor and resistor/controller. It happens a lot that connectors overheat and melt due to resistance. Also check the blower fuse if its not blown.
If all this seems to be ok, its probably the resistor pack/controller. (with manual temp control system, you have a resistor pack, with the AZC system, you have a controller)

D-Money 07-25-2011 04:28 PM

Re: Low vent air pressure
 
Ok I will do that. Is all that the same on a Limited, because thats what i have (sorry I forgot to specify that). And is that fuse under the hood or under the dash?

Frango100 07-25-2011 05:59 PM

Re: Low vent air pressure
 
Its fuse 1 (40A) in the PDC under the hood.
Limited should have the blower motor controller and not the resistor.

CAJeep 07-16-2013 11:51 PM

Re: Low vent air pressure
 
I have a '02 GC Overland and the blower stopped working so I took it to a local shop to have it fixed. They said it was the blower motor resistor and thus replaced it. The fan does now turn on, but the air pressure coming out the vents on High is equal to what Low used to be -- similar to the initial Post here, the High pressure is like exhaling lightly from your mouth... even though it "sounds" like the fan is blowing hard, not much air flow comes out of the vents.

And btw, this might not be accurate, but I THINK the fan blower actually sounds different now as well, kinda has a slight whine to it...

So I'm wondering if they installed the wiring wrong on the new resistor or if they messed something else up w/ my vent system (kind of sounds like something is blocking the air flow). All vents work, including the blend doors and moving from upper and lower vents -- so that system works fine.

Any ideas / tips? Appreciate the help.

Frango100 07-17-2013 06:55 AM

Re: Low vent air pressure
 
Connecting the wires wrongly will result in the blower turning in the wrong direction and blowing almost no air at all. So probably this is your problem.

CAJeep 07-17-2013 10:01 AM

Re: Low vent air pressure
 
Hey Frank.

Thanks for the quick replay and advice. I believe you are correct. After more research on-line late last night, I re-wired/reversed the 2 wires connecting the motor resistor and the blower, and it now seems to work perfectly. Can't believe that Chrysler/Mopar sells a brand new part, to fix an earlier defective part, that now knowingly has those 2 wires reversed...

Makes me wonder about the overall quality of all of the parts in my Jeep...

Frango100 07-17-2013 06:31 PM

Re: Low vent air pressure
 
You are not the first one where this problem happened. Normally the problem with the blower motor controller is not the controller itself, but the connector on it. The connector doesn't fit the pins well or over time they get some play due to vibration, and the resistance caused by this, heats up the connector and the plastic melts.
MOPAR has a new connector with wires, but the wiring colours seem to be wrong.

EricDC 07-22-2013 06:04 PM

Quote:

Originally Posted by Frango100 (Post 860089)
You are not the first one where this problem happened. Normally the problem with the blower motor controller is not the controller itself, but the connector on it. The connector doesn't fit the pins well or over time they get some play due to vibration, and the resistance caused by this, heats up the connector and the plastic melts.
MOPAR has a new connector with wires, but the wiring colours seem to be wrong.

Frank,
I just had the same problem as CAJeep; A/C blower quit working, shop replaced the resistor (controller) and connector harness. Blower then worked but very low air flow. They tried to repair it by replacing the blower motor but same thing. They said they replaced many of these and the air pressure always falls because that's just the way the new resistors work.
They suggested I take it to the dealer, but I knew I would get ripped off, so researched and ran across your post. I took it back to the same shop where they reversed the wires on the new harness.....it works perfectly and they now know the fix for other victims of these flawed new parts. THANK YOU!

Frango100 07-22-2013 06:27 PM

Re: Low vent air pressure
 
Quote:

Originally Posted by EricDC (Post 862944)
Frank,
I just had the same problem as CAJeep; A/C blower quit working, shop replaced the resistor (controller) and connector harness. Blower then worked but very low air flow. They tried to repair it by replacing the blower motor but same thing. They said they replaced many of these and the air pressure always falls because that's just the way the new resistors work.
They suggested I take it to the dealer, but I knew I would get ripped off, so researched and ran across your post. I took it back to the same shop where they reversed the wires on the new harness.....it works perfectly and they now know the fix for other victims of these flawed new parts. THANK YOU!

Good to know it helped another harness victim. I have never seen this harness myself, but wonder why Mopar doesn't change it if its made wrongly............

CAJeep 07-22-2013 08:41 PM

Re: Low vent air pressure
 
You'd laugh if you saw the "wiring harness" and how simple the fix is, and thus how idiotic the "manufacturing defect" is. It's basically two wires, one green and I think one white, both with male wire connectors on each end and then pushed into little plastic "clip" housings that clip into the blower motor on one end and into the new resistor part on the other.

Seriously, someone should write to Mopar and let them know... It literally took me less than a minute to pull out, reverse, and re-insert the wires. And of course after my "shop" couldn't figure out what the heck was wrong w/ my low air flow... Like EricDC, my shop wanted to start replacing other parts because they were 100% sure something else was also broken in my Jeep, it definitely couldn't be the result of the work they just did...

Thank you JeepGarage.org! An excellent example of the power of the internet and good 'ole boy knowledge from the Post'ers on this site! Thanks everyone.


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