The only thing I can think of would be the ABS pump kicking in, IF you have 4 wheel ABS. It shouldn't be however.

 

hi Dan,
Thanks for the info, Dodge is ordering one of the valves in now.

To all future readers of this, it is NOT called a Hvac check valve (at least at chrysler in Alberta Canada) , they seem to call it a valve check, or on Napa's website a Distributor Vacuum Advance Check Valve, or Vacuum Delay Valve, Dodge Part # 4549209 Valve Check.
Autozone part number: # 47149
Napa part number 2939 : Distributor Vacuum Advance Check Valve, or Vacuum Delay Valve

I hope this helps someone, as Dodge cannot locate this part for you, we went to 3 different dodge dealers and all tried to resell us the same brake booster check valve, informing us that there was no other check valve in the line. We were forced to look it up on our own.

 

Dodge doesn't seem to find the part as HVAC. It's listed as A/C Bypass, or valve check, Dodge part # 4549209, cost is around $6.00. Auto Zone ,Motormite, part number 47149 for $5 . and NAPA part # 2939 called Distributor Vacuum Advance Check Valve.
They are an ongoing problem for more than just dodge. Can cause problems like squealing noises to crazy vents (radical air vent switching), or cruise control issues. Not sure on all the symptoms but thats the few I've heard of so far.
Hope this helps others some what.