Alright, so then the 7854 is no go!
That leaves me IR7478PBF.
No documents for the control unit states that there should be any PWM.
Also, it seem to be very uncommon for this to be PWM controlled. It turns on until the engine heats up, then there should be no heating happening.
I will however check the signal again once i have mounted the 7478 just to see.
About the gate charge, am i reading the diagram correctly if i say they compare like this:
Vgs: about 5
Qg: 25 (7478)
Qg: 12 (HAT2033)
What is the recommended value here for a PWM application?
Also, i do hope that the 2033 is really the HAT2033. Otherwise im in the deep end!