Several years ago my 1996 1500 starting switching the air circulation from the main vents to the defrost whenever I put a load on the engine by accelerating. It doesn't matter if the A/C is on or not, Recirc or fresh. I have NO idea what could be causing this. I have reset the computer but that didn't help. Any ideas

John

 

Here is the info for "crazy vents" or "wacky vents". Do a search and you will find a boat load of threads.

It's a common problem.

https://dodgeforum.com/forum/2nd-gen...help-guys.html

https://dodgeforum.com/forum/2nd-gen...ild-vents.html

 

There is a vacuum line issue most likely... I had the same problem with my 1996; my mechanic told me it was one of the vacuum lines he replaced it, and it fixed my problem... If that is your problem then it is an easy and inexpensive fix. I would get that checked out before spending any big bucks...

 

It generally is going to be the line with the little white and black check valve in it. Sometimes the check valve itself just goes bad and doesn't hold constant vaccum to the dash feed.

 

the crazy vent advice worked. No more issues. Thanks again

 

Our work here is done then.