I had a 99 SD that had control ***** for heat and A/C. In that truck, it was my understanding that when you turned it to Max A/C it simply closed the vent door and recirculated the air and the air started blowing out faster. I recently bought a 05 SD Lariat and it has the electronically controlled heat and A/C system. When I have the A/C on and push the Recirculate button, the Recirculate light comes on but I don't notice any difference in air output or air temp. I took it to the dealer, told them about it and they said there was no problem. Is the 05 SD supposed to blow out air faster or significantly cooler when on Recirculate? Thanks.

 

I dont know about speeding up the fan but recircing in the truck can be found out if you have a dairy near by. I live by many of them and you darn sure know quite quickly if you forget to turn it to max a/c b4 you get to one.

 

Recirculate button? My 05 Superduty XLT doesn't have one. My understanding was that when put into max ac it recirculates.
Okay, now I gotta go out there and look but I'm sure I don't have that button.
I have read of people complaining of diesel fumes in the cab of the truck, who had come to find out that it was actually other trucks on the road (or their own exhaust at a stop light) that they were smelling. When they turned on the max ac, the smell went away. At least that is some of what I read on earlier posts.

Onions, that's funny. Good idea but pretty darned funny.

 

The button doesn't have the word Recirculate on it. It's a picture of a vehicle with a U-turn symbol in it. When you push that button, you see a light in the display showing about the same image. It may be referred to as the Max AC button, but a service manager told that's all Max AC is, closing the vent door and recirculating the cab air. Again, nothing seems to happen when I turn it on recirculate. I'm trying figure out whether it's working by asking here before I have to perform the dairy farm test or in my case here in eastern NC, the hog farm test.

 

I just bought a 06 SD and noticed the same thing on mine,usually on my past trucks(GM) it would blow out harder when the recirculate button was pushed and blow 40 deg.. Mine only blows 58 deg air also,I only have 120 miles on it so I was gonna drive it for awhile and see if it needed some miles.. To me the air isnt blowing cold enough.

 

my 05 when i turn the dial all the way to max ac it definatly recirculates. the air does travel faster and make a little more noise as it is pulling the air from inside the cab. It also is colder, as thats what recirc does, instead of trying to cool outside air, you maintain the inside temp, so no fresh air, and no cow smell.

If you can sit in your truck, turn the fan to say speed 2 on reg ac, and if you then turn the dial to max ac, and you cant hear any difference at all, i would definatly say its not working correctly.

 

This is the electronic temperature control AC system. There are no dials or *****. You press a blue button to turn the temperature down, you press a red button to increase the temp setting. It does not have a "Max AC" button or setting. It does have a re-circulate button though but there is no change in the air flow when you turn re-circulate on or off.

 

if you select auto it comes on in recirculate. if you leave it on long enough recirculate will turn off and you will notice a reduction in airflow. but if you want to check it, turn the ac off and select a/c instead of auto then turn the fan speed up manually then select recirculate and you will feel and hear the air flow pick up, then turn recirculate off and you will feel and hear the air flow go back down.

 

Boy am I dense. Figured it out with input from everyone. I have to remember to get it off Auto before any other function works.