HSF-3, pump not working

[FrisbeeGTI]

Hi.
I've got earlier some problems with HSF2/3 pump. The pump was assembled in a wet location and the pump seized and started to blow fuse. Opened the pump, it was rusty inside but got it spinning and gave some lubrication for it, sealed the pump and assembled it again. I also soldered the dropping resistor mod on the board . It worked fine for a while.

But today it seemed to spray ok some time in the beginning of ride, and then stopped working. I didnt see the gauge light but is was sunny day and i'm not sure... Got home and noticed that when i put the ignition on (but not starting) the pump starts working (sounded noisy) and doesn't stop at all if ignition is not turned off. It did not matter if the gauge button was on or off. If trunk, power or gauge connectors were unplugged pump didn't activate at ignition on. The gauge button didn't give light anymore on or off. There is enough water+meth in the tank.

Took the relay away and put it back (the relay connectors had some rust), checked connectors and earth connections which were ok. Fuse was ok. After that the pump didn't activate at all anymore. When I put the FAV connector to SYS the pump doesn't activate (THRES and 95% give the light). Fuse is not blown. Tried to give straight 12v to the pump connectors from battery but nothing happens. IDC light is blinking properly when motor is running.

I have to open the pump again. But why was the gauge button light dead? And why the pump activated when ignition was turned on and continued to give noise? I'm just thinking what parts I have to replace.