First off I'm not talking about the MAF sensor! There is a valve on the L/H lower side of the air intake filter housing that one of the small vacuum lines coming off the front of the filter housing attaches to. i'm not sure what that exactly is. any help would be appreciated. It's a 2001 S80 w/ 2.9L (non-turbo).

 

That allows a flap in the airbox to move to allow warm air from the exhaust. I had to replace mine as it didn't respond any longer.

 

do you know the name for it? I can't seem to find it anywhere I look to see about getting a replacement. I'm trying to trouble shoot this valve to see if it has any relevance to my current problems. If I'm not mistake it pulls warm air from the exhaust heat shroud on the exhaust manifold. However, I'm confused as to the parameters as to when it is suppose to operate and the desired effect it plays in the intake. any explanation would be greatly appreciated.

 

VIDA does not list this part. Its all part of the airbox. But it is controled by the sensor where the two vaccum lines connect. Part number 9209888. What I did to test the funtion was to suck on the vacuum line that controls the flap movement.
If the temp is cold, the flap stays closed to allow the warm air to come in. Once it reaches a certain temp, then it allows colder air to come in. This is from memory and think this is correct.
I just replaced the entire box from a scrap yard and it included the MAF sensor as well for a bonus.
In the long run, I notice no change!
What problem are you having?