So after having a car for about a year I found out there is webasto fuel burning heater in it. Better now then never

It has never started for whatever reason (despite really cold winter) and I wanted to fire it up. I have sdd so I gave "Auxiliary heater activation test" a try. The test was supposed to run my FBH for 135 seconds but it failed immediately after 1s. So I run "Auxiliary heater priming routing" hoping that if it was not used for years then maybe fuel is not there. In fact the first test failed to provide any diesel, but the second try gave me nice bleed. Unfortunately that didn't help. Activation test fails as before (immediately) and FBH is not starting when its cold.

I did my research and found out some guys did some wiring to connect the FBH to webasto software to run it. However having sdd this should not be needed, right? Is there anyone with an idea on what could potentially be wrong? Fuse 28 under the bonnet is ok, there are no error codes related to FBH. Auxiliary heater module self tests runs successfully.