cooling fluid pumps - 2,7 cdi / Webasto

Hi

could any one name the functions of two water pumps located on the right side?

- the first one - horizontal, activates with key turn. I assume it shall support fluid circulation by low engine speed.

- the second one - vertical - lack of electrical signal, even at the engine start. (!?)

In my car none of them receive electrical signal from Webasto at its activation, although the horizontal pump is often called as Webasto pump. I have problems with fluid circulation after initiation of Webasto. It works, pump pushes hot fluid to the interior but Webasto overheats rapidly and switches off (in a 30 sec or so).

In course of searching for the reason of such malfunction I thought it may be a problem with any additional water pump that may be designed to cause proper circulation of the fluid.     

I tried to check if any of the receives electrical signals at Webasto initiation. It turned out that - none. The vertical seems not to receive the signal at all..