Hi I'm going crazy over my car...

It all started with my wife telling me that the car was stuttering alot when she went home from work. So I took the car out for a ride to see how the car was acting.
When I arrive at a crossing the car just dies and when I try to start it again it just starts for 1-3 seconds and immediatly dies.

The diesel meter has been kinda sketchy recently even tho the tank is half full it says it's empty. I was sure there was enough diesel in the car but just incase i brought can of diesel and poured it in to the tank.
Nothing changed still the same issue, so the car was never out of diesel. So was starting to think of issues with battery or the fuel pump.

I've tried to change battery without any effect of it at all and the generator seems to be loading aswell. However when I was testing things out with the car I drained the battery.
So I took my second car to try startup with cables and it worked. The car was running for over 20minutes without any issues but the instrument panel, turn signals and window lifts didnt work. But mechanically the car was working just fine.
When I restarted the car I was back on square one. Starts perfectly just to die withing 1-3 seconds. So I tried once again to drain the battery and startup with cables and it worked with the electronics mentioned above freaked out once more. But overall car was running fine.
AC and Radio was working for some reason and lights around car except for turn lights was working.

Anyone has some experience with this or any clue where to start? Should be some electronics issues right?