basically just like the subject line reads. my max a/c isnt blowing any harder or any colder than the regular a/c. anyone know how to fix this and/or whats causing it? everything else works like normal (defrost, vent, etc.). i wouldnt think it would be a fuse considering that the a/c works. just the "max" doesnt work properly. hmm? thanks for the help in advance.
dave

 

The MAX setting should close a vent that lets in external air. It should blow harder and colder on this setting. More than likely it is a check valve or vacuum leak causing your problem.

 

okay, i apologize ahead of time for being a tard. where exactly would i check for these problems? i'm not exactly familiar with where the check valve would be or where to check for a vacuum leak.

 

It does not really blow harder, because the fan speed does not change. It usually sounds like it is blowing harder, because as dave says, it closes the fresh air vent and uses the inside air to run through the cooling coils. You now hear the intake side of the blower and it makes more noise (sounds like it is blowing harder). It feels colder because you are now cooling air that should not be as hot as the outside air and it's easier to cool down.

When I first get into the car on a hot day, I don't use the max setting right away, because often the inside air is hotter than the outside.

As a little history, the max setting used to be called "recirculate". That term is actually more accurate, because that is what it does-recirculate the air inside the car.

 

I swear it feels like it is blowing harder when it is on that setting. I absolutely understand that the fan speed does not change. But for some reason it seems to blow harder. I think I know why, hear me out....

If it is blowing air from outside in. The it will be raising the pressure in the cabin. If it closes off this external source and recirculates the air the pressure would lower therefore allowing it to blow harder?

Who knows it sounded good at the time...

 

hey that cool. i didnt know that about the fan speed. ive seen some foreign cars still using the recirculate terminology. however, my car is not recirculating then. because i can switch from regular a/c and max a/c and not a single bit of difference. i used to be able to hear it switching to regular a/c or vice versa. now i hear nothing and dont feel a single bit of difference. it definitely doesnt blow as cold when its not recirculating!

 

Do you hear the vacuum release when you switch between normal and max? How about the other settings? If not I'd say you have a constant vacuum leak somewhere between the vacuum source and the dash.

 

Is it the Marines that makes you stubborn or were you like that before joining up? j/k

I don't really know. I guess Fred will have to field that theory. He is the pressure dynamics guy. I would only think it might blow harder if somehow the air being pulled in from outside was impeding the fan flow and no impedance in max.

slverbullet:

You might be able to use some of this info that I just posted on my page. It is some stuff I had already written up and just got around to adding. Some of the vacuum testing might lead you to a leaking actuator or hose connection that is keeping the max feature from working (check the diagram).

 

I think its a combination... I over analyze everything. Thats probably why they have me doing, "what they have me doing"