Could someone please tell me if the water controll valve on my 1980 240D should be hooked up to the water pump or to the back of the head?

Right now it is hooked up to the water pump and the hose from the back of the head goes to the heater core single outlet side.

The diagram I find for the cooling system makes it look like the coolant should flow from the head to the watercontrol valve through the heater core and back to the water pump. If this is correct then my car is plumbed compleatly wrong.

Right now my car only has heat on one side. So I disconneted the two hoses from the water valeve to the heter core to check for flow. What I found was water flowing out of the heter core not out of the valve which is opposite of what I expected to find.

Can anyone please shed some light on this for me? Mabey take a look at your car and see how it is plumbed?