poor HVAC air movement, plenty cold air???..

[DZink24]

ok, again with the whole HVAC issues. i have looked thru the vast posts and replies in regards to the poor A/C and or HVAC ducts in our trucks, but here is a new one. . for the second summer in a row, i just returned from a 600+ mile round trip vacation to the Adirondack mtns. and for the second year in a row, the volume of air that the blower motor moves after several hundred miles of driving is comical. it sounds like a jet engine behind the dash, and yet NO air is coming thru the vents. any of them. the knob is at the full blast position, and none of the vent positions work. not recirc, defrost, any. i find it weird that this happened last year as well, but it does not happen in trips less than a few hours/few hundred miles. i did however, seem to hear what sounded like leaves, or papers behind the dash, something that will possibly block the flow of air. the coldness is fine, and i know that the blower is turning, but there is a blockage somewhere behind the dash. have you guys with "blend door" breakage had the same issues, or is it a particular position on the dial that it will not work?

 

[Wingate]

Had the blend door issue about a year ago on my truck..... Sounds the same to me. Fan motor running wide open, but nothing coming out of the vents... doesnt matter if you put it on face, foot, or defrost... . you might get lucky and find a trickle of cold air somewhere. Seems like I was able to get bent around enough in the passenger floorboard to see that the door was broken off the little drive assembly. I might have taken the glove box out, can't remember.

Anyway... what I'm wondering is WHY it always happens when gone on vacation...

 

[AWise]

Just went through this. Its the recirc door above the motor and fan. The door breaks off and the little piece falls into the fan blades/squirrel cage, the door falls down and covers the blower intake. I just pulled the fan motor out (drops straight down), pulled out the piece in the fan, and then reached up through the fan hole and pulled out the broken door. The fan blows harder than it ever has now. It has worked so well this summer even at 100* that I dont plan on putting it back on anytime soon.

 

[DZink24]

i just went out and looked, got underneath the passenger side dash, the housing for the blower motor was dripping, soaked, wet. so she's definitely making cold air... . i bought the extended aftermarket warranty in 11/2005 when i got the truck, i'll let the dealer handle it. . can't wait for them to tear it apart to fix it, so something can rattle after they put it back together.

 

[ryecreek]

ITS FROZE UP

you prob have the blend door issue or are low on 134

i currently have my air box apart for a heater core but,

the blend door(fresh/recirc) has broken stops and the defrost door is toast(broke at shaft)

your door may be stuck to outside humid air causing you to ice up when it does it try the heat and no a/c for 1-2 min. and i bet it will blow fine

 

[DZink24]

the weirdest thing about all of this is that granted, yes,the A/C volume (not the temp) is pathetic all the time, this "no air" issue only seems to happen after driving for several hours, mainly at highway speeds. i remember last summer, i was literally 5 minutes from home after 6 hours of driving when it went kaput. today i was probably 3 or 4 hours into the trip when it decided to not work anymore.

 

[BHanna]

If it only happens after driving for a few hours and then is fine after sitting for a few hours, I'd bet the evaporator is freezing up. That usually happens when your refrigerant charge is a little low. Moisture under the dash is another good sign of a frozen evaporator.

 

[AWise]

ahhh, yea, I would have to agree. If it only happens after driving a while I bet your refrigerant is low, causing the coils to freeze solid. I thought it was all the time, wouldnt hurt to check the recirc door anyway just to make sure. I didnt catch that part about it happening after a few hours and then going away.

 

[DZink24]

as i think about it more, i recall the heat working fine in the winter, no issues with air movement. i will have to check into the freezing coils a bit more.

 

[BHanna]

If you want to try a quick fix yourself, you can try one of those cans of R-134a with the gauge and hose on it. You probably have a little leak though. The easiest thing to check for leaks would be the schrader valves. I have one that has vibrated loose a couple times so I've had to snug it back up and add a little freon.

 

[raksasa]

I had the same problem a few weeks ago. I began a 2 hour drive with everything working fine on a really hot day. About 1. 5 hours into the trip the A/C was making lots of noise and putting out lots of nothing. Changing the vent and recirc settings resulted in no change. Conditions were hot and humid and I had been running in the recirc setting most of the drive.

I arrived at my destination and the truck sat for about 2 hours. When I was ready to leave I noticed a river of fluid flowing out from under the truck. I popped the hood and water was gushing out of the A/C drain on the right hand side of the firewall.

On the return trip everything worked great. I cycled through all the settings many times with no problems noticed.

I'm thinking that running in recirc so long might have contributed to the problem.

 

[DZink24]

oh, the irony... the A/C blows too cold. so essentially, there is actually ice building up on the vents, much in the same way that a refrigerator/freezer will build up ice over time if not thawed occasionally??

 

[ssanders60]

I had the same problem in 2003 quad cab 2500. It was freezing up on road

trips, but not intown driving. The evap. or condenser behind the dash

was leaking and it was low on freon, the repair was replacing that part

and repair to the blend door. That has been about 3 yrs. ago, no more

problems.

 

[RVTRKN]

oh, the irony... the A/C blows too cold. so essentially, there is actually ice building up on the vents, much in the same way that a refrigerator/freezer will build up ice over time if not thawed occasionally??

Low pressure control not openning on the proper temp/pressure. Temperature/pressure relationship with R134a should set the control at a pressure just above freezing to prevent iceup and destroying the evaporator. If you are forming ice then there is a serious problem and it is good that you are having it checked out.