Blend door problem?

[JBDive]

This has been going on for several years and I just deal with it however I just spent a ton on a new engine so I'm in the mood to get everything working right.

A/C on outside air blows like mad through the vents. When you put it on recirculating air 90% of the air is dumped into the dash, not the defrost, floor or vents, it just disappears into the dash.

Could the actual A/C-Heater control box be bad? I have tried the right/left/right/left re-calibrate trick but it does nothing and I understand that is the case with the 02, the trick works on 03 and up.

 

[Billwill]

On defrost on my 2002 Export CRD I get very little air coming out anywhere except from the demister vents on recirculate...always been that way.

Check the vacuum pipe from the intake manifold going into the cabin has not come off, kinked or has splits or else the blend door will not work properly.

There is a metal grid just below the glove box on the bulkhead to expel air.....this can get clogged up by dust so locate it and give it a good cleanup with a brush and vacuum cleaner

 

[JBDive]

On defrost on my 2002 Export CRD I get very little air coming out anywhere except from the demister vents on recirculate...always been that way.

Check the vacuum pipe from the intake manifold going into the cabin has not come off, kinked or has splits or else the blend door will not work properly.

There is a metal grid just below the glove box on the bulkhead to expel air.....this can get clogged up by dust so locate it and give it a good cleanup with a brush and vacuum cleaner

No there used to be a lot more air on re-circulating than now but it has been years.

Engine was just replaced by a dealership (only because I get a labor deal) so I know they would have noticed a disconnected hose and fixed that and would hope they would have noticed a really bad one plus if leaking from the manifold then none of the vacuum related settings should work.

 

[JBDive]

Solution Found!

After searching the Internet for years, asking questions for years and everyone always going for the worse case of dead A/C, broken vacuum lines to who knows what else I was able to fix my problem in less than 10 minutes today.

In my search for answers I found the following site:
"How to fix Jeep Liberty blower motor (resistor) – with pictures"

A few steps down in this post there is an image of the blogger pulling the wiring harness but I noticed something in that image, what looked to be a filter far up in the dash behind the glove box.

You must be registered for see images

So I drop the glove box as I have done a number of times before, got out the high power flashlight and low and behold way back up in there is a filter or mesh vent if you like and it is covered in lint, dust and crud. A minute or two with the shop vac and everything was as clean as when it was new so now time to test.

I start the car with the A/C in the outside air position and fan on #3. Vent pressure is good as expected so as I watch the mesh filter I switch to re-circulating and right there behind the mesh is a blend door and I watch it open up wide and as it does there is no change in the air pressure coming out the vents. Problem Solved!

 

[Leeann]

There is a metal grid just below the glove box on the bulkhead to expel air.....this can get clogged up by dust so locate it and give it a good cleanup with a brush and vacuum cleaner

That’s what Bill was talking about in the above quote.

 

[JBDive]

That’s what Bill was talking about in the above quote.

I didn't see any other filter or grill under there. Intake was the problem, not output, at least not under the dash.

 

[Leeann]

As I said, what you cleaned is what Bill was talking about. It's a common problem.

It might be in a different place on his export CRD.