whooooo... you snuck that in.. do tell... not heard about a foot switch... what does that do?
all kinds of ways to control a pacbrake, a floor mounted foot switch I suspect you simply Press sw = brake on, release sw=brake off.
It could also be tied to the brake light circuit so enough brake pedal to turn on the 5PSI brake light switch rolls on the ex brake valve.
I liked the config the last truck i drove that had one used. Had a master on/off sw and the ECU used throttle position and RPM for control. Any throttle = brake off, release pedal = brake on until you dropped close to idle RPM then brake off. You want to go, you press the pedal you want to coast, hold very light pedal, you want to slow, release pedal, want to really slow shift to brake pedal. Very easy and intuitive control i left the brake sw on all the time, and didn’t use the brake pedal much except when I actually wanted to come to a stop…
will need some kind of pulse count/RPM sense circuit to implement this method on my A0 pac brake, but a left foot switch could also serve the master on/off control in place of an RPM sense, to allow the throttle sw to then modulate the butterfly valve.
the thing with ex brakes is you really want to exercise them regularly to keep them healthy. I think pacbrake even makes a controller that does this automatically at every startup…