Sorry, made a mistake above ( I do not have Sport Chrono)

If you want ALL options with the Sport Chrono,you will need an ON-OFF-ON switch , not a DPDT as stated above.

( Pos.1 ) ON = PSE will work exactly per factory .

( OFF ) = PSE will ALWAYS be LOUD, regardless of Sport Chrono settings( interrupts power to solenoid valve )

(Pos.2 ) ON = PSE will ALWAYS be QUIET ( alt. 12V power closes valve)

Please keep in mind that I do not have Sport Chrono in my car so I can't test the above .So do the install at your own discretion. You may find an easier way , using a relay .
I have no way of determining what happens in the car's computer circuit . It's one thing to interrupt the power supply to the solenoid and another when introducing voltage from another source.
To be safe, I would keep the two power sources completely independent . That way you can be sure that nothing can adversely affect the cars computer circuits.

(I have the PSE switch , installed the disconnect switch and everything works great).