Thanks for the reply.
Link to full instructions.
Under "Installation Wiring Option 1: Hard Wiring ETS-PRO" you can read the following:
If hard wiring the ATTESA pump motor, the pump will require a simple 12V 30A Bosch style relay and fuse – similar to wiring a fuel pump and available at most auto part stores like NAPA. The ATTESA pump has a built in pressure switch used to disconnect voltage to the pump when max pressure is reached, this pressure switch should be used to “interrupt” the low side of the relay
Some customers may opt to leave the entirely stock atessa ecu and wiring in place, but disconnected from the actual PWM solenoid, Instead running the ETS-PRO directly to the solenoid. The only thing to do is the mandatory 5 wires, and optional sixth is the ebrake or 2wd cutout – this is the easiest and fastest way to install and retain MFD functionality(installation update for R34 update will follow).
In the photos attached you can see that the pressure switch has two wires coming out and in the circut diagram its the same.
This is the part I don´t understand. I can connect a new relay (I have read that a 40 Amp relay is needed here on SAU) but since there is two wires, how does the pressure switch work and how is the two wires supposed to be connected?
Thankful for your help!