Hey guys can anyone identify this part. I know it a vacuum control switch for rear heat....I think,
but what is it call actually. Thank you in advance for any help.

 

This the control valve I had gotten from napa
It's the heater control valve, didn't see one available on rockauto. Should be able to find on Ebay or amazon with your van's info and might get lucky at one of your local parts stores...

my bosses 2000 3500 passenger van's valve blew up one hot summer day driving through town, my 99 3500 cargo one crumbled apart while attempting to pull hoses to do a flush about 4 years ago.
Think he ordered new one from the dealership here, I found one that was not identical but works from napa, as I needed it right away at that time.

 

Thank you JF for the quick reply. The control valve controls the coolant going to the rear coil correct and how is the valve from napa working for you? Have you had any problems with it? Sorry I forgot to say the van is a 2001 5.2 Regency conversion.

 

The napa valve seems to have been working fine over the past 4 or so years. A year or so ago I had noticed that the vacuum line attached, which on mine, is white and runs back through the firewall to the temp control was not producing any suction and valve would not operate. That's with temp dial set to max cold and ac running... I found that the first few inches of the line was bad, broke in two easily with not much pressure bending it.

Luckily there was enough good section to reroute it in front of the pcm and reach the valve. I'm sure this remaining section as well as some of the other lines will eventually need replaced. For now it's been working.