Recirculation Kicks To Fresh Air Every 30 Mins Like Clockwork

Jean-Pierre Diagnostician Springfield, Oregon Posted   Latest  
Question
Electrical
2008 Dodge Sprinter 2500 3.0L (5 EXM) 5-spd (W5A380)
Recirculation Door Inop

Hi all, I have a 2008 sprinter van that when you have the ac running and blowing cold just fine with the recirculation mode selected, after 30 minutes of running in recirculation mode the light on the switch goes out and the recirculation door changes to draw in fresh air, all by itself. While observing module request of recirculation door, every ten minutes it sends request to recirculation door motor. at 10 minutes, it sends recirculated air message. At 20 minutes it sends recirculated air message. At the 30 minute mark it sends Fresh air message then the door switches to fresh air mode, all on its own. I've tried to perform a relearn in the hvac module for blend door positions with no luck. Right now im performing a brain kill to see if I can reset the module that way. If anyone has come across this condition before some insight would be greatly appreciated, before I condemn the HVAC module. thanks again

0
Dave Owner/Technician
Novato, California
Dave Default
 

This is normal... Recirc is not allowed to be constant due to the possibility of CO2 buildup causing drowsiness. All Mercedes products are this way, probably all Euro cars, maybe all cars?

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Interesting
Richard Instructor
Palmetto, Florida
Richard Default
 

this is normal operation, in order to prevent drowsiness. There’s no need to replace anything.

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Jean-Pierre Diagnostician
Springfield, Oregon
Jean-Pierre Update
 

Thank you guys so much, much appreciated. Now ill know for the future

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