97 Aerostar. A/C MAX vs NORM.

[djkrawietz]

Can anyone tell me the difference beyond in/out air between MAX and NORM settings of A/C on 1997 Aerostar? Why would air coming out of vent be okay in NORM setting, while it is intermittent in MAX setting? It can blow just as strong as NORM or a bare-amount. Is it related to amount of refrigerant, a/c clutch compressor, vent actuators...

 

[mr2fix2it]

you have something blocking the max ac door under dash usually behind glove box possible plastic bag?

 

[patrick112390]

all it does is opens a door behind the glove box, and draws already cold cabin air, instead of outside 100* air. as for your concern, i cant give you an accurate internet diagnosis lol :

 

[djkrawietz]

Thankyou! I seem to recall taking van in to shop about the a/c flow and they said they had found a plastic bag blocking air. I took a quick look underneath dash and did not find anything, but will take another closer look later. There is a big plastic cover under the dash and glove compartment, so it would take alot for some obstruction to get to the door, but I am sure it can happen.

 

[BrooklynBay]

Welcome to this forum! I've moved your thread into the Aerostar section. Did you check the pressure of the system with an A/C manifold gauge set? Did you check the hard plastic vacuum tubing near the servo, and check valve for cracks?

 

[djkrawietz]

Thanks Brooklyn Bay,
No, I have not thought to check pressure, but would assume there would be a change in pressure when the air is blowing fine and when it is almost none. The problem is intermittent and will see if I can get it checked when it is blowing good and not blowing so good. It makes since to check the hard plastic tubing due to age, and because a hole was found in the a/c somewhere previously causing a loss of air through the vents. My manual does not show the check value or servo. Where would it be located?

 

[BrooklynBay]

They are next to the blower motor housing in the middle of the vehicle under the hood. Sometimes the low pressure cycling switch goes bad, and causes intermittent clutch cycling even though the pressure in the system is normal.

 

[djkrawietz]

Thankyou BrooklynBay. I have alot to checkout this week