Originally Posted by Cougar41

You won't find a control valve on these vans from at least the 3rd generation (96-00) vans forward and probably even earlier than that. Coolant flows through the heater core all the time. An electrically actuated door in the HVAC unit controls how much hot air enters the cabin.

Bad thermostat? Are you seeing a slower than normal temperature gauge increase as the engine warms? Is the upper rad hose cool or only warm 10 minutes after starting?

I only learned of this restricter from this recent thread (linked below). This is all I know about it. No idea if your van has one. The last post on the second page may say it all.
https://dodgeforum.com/forum/dodge-c...rol-valve.html