I know that this has been hashed over many times but I am puzzled by a few different things I cant remember reading, I know I probably did but memory is just about as good as the vans Vacuum system.
We have a 5.9 automatic 3500 van, when you idol the ac on normal it is dash forward only: when you put it on bi air it is forward and defrost vents?
Now when you are on normal and put a load on it the air goes from the dash to defrost only.
I understand the going up to defrost when the air is on and put under a load but I don't understand why the air is bi level and going to dash and defrost, is this also a sign of a vacuum leak or is this a sign someone has routed the vacuum lines wrong in the past this is a new to us vehicle????
I thank you for any info or direction
Grumpy

 

Defrost is the default position when there is a loss of vacuum to the air flow door actuators under the dash. The condition you described is the result of a cracked but still attached vacuum line or the HVAC vacuum check valve is leaking.

 

or bad/disconnected vacuum reservoir ball also. had similar defrost/vent issues, that was my problem.

 

If it were disconnected then he would never get air to blow out of the vents, that's why in his case it's a leaking vacuum line or a faulty check valve.

 

the check valve you refer to is the small plastic in line valves???? or is there others I am unaware of???? I have 2 of the small plastic ones, one on the manifold and one near the heater ac controls both are good.
Thanks
Grumpy

 

On mine it is located in the vacuum line that comes off the passenger side of the intake manifold.

 

Thanks for all the help, I found about 12 leaks in the sets of tubing in behind the ac heater controls with the cigar smoke. Then we found a new and serious problem ; The blend door vacuum actuator I think is the correct name. It is the vac can behind the passenger headlight that has about a 8 inch rod going rearward to a door or ? and looks like to pie pans apx 3 inch diameter banded together. Has a vac line on each side.
This vac actuator thing has a large , half the size of a dime hole rotted in the bottom on one side.
Now this is definitely the problem that remains BUT the problem I have is
DODGE does not make the part any longer: No dodge dealers we can find has any left in stock.
Does anyone have any suggestions on the replacement of this part: We are in Phoenix and needless to say the ac system is a MAJOR requirement
Any help greatly appreciated; And thanks again for the help on all the other vac leaks ; Cigar smoke really works good especially when you cant hear :
Grumpy

 

Glad you found the problem.

Is this it?

http://www.moparpartsoverstock.com/p.../04723550.html

or you can hit up a junk yard in the area or online

or ebay

or you could make your own from a fancy travel coffee mug.

 

That is the fresh air/recycled air door. When you switch to Max A/C vacuum is applied to that actuator and the door closes. This causes the air in the cabin to be drawn into the A/C to make the air colder than it would if hot outside air was instead being drawn in.

 

Ok got that actuator replaced; Had to go to the salvage yard and find one to get one ours had big hole in the can. NOT available in the world today by any new method I could find.
NOW I have all the airflow in the proper order with the Max air flow and all but I still have a problem.
The air on BI LEVEL pushed in goes to the front of the dash as should and instead of lower ducts it goes also out the Defrost So I have defrost and front of the dash instead of front of dash and lower on bi level;
Now does anyone have any idea which of the two actuators on the top under the dash controls this issue????? I m really hoping to find a hose problem but history of this beast tells me its an actuator up there?????
Thanks very much for all the great help we have gotten here
Grumpy