nitrous triggrer input?

[aceman187443]

I want to hookup nitrous on my 93 prelude with s300 (white board) installed on p75 odb1 ecu. I will be using the a/c switch pin (b5) . Is it possible to use the switch in the dash with its existing wiring to trigger "ARM", if I simply set the nitrous input in the smanager to b5, Or do I have to snip b5 at the ecu and wire in voltage from a arming switch? If I have to use a switch then is it by default 12v+ or 12v -? Thanks a million for your support on this subject

[Spunkster]

It will not work in stock form that way. You will have to custom wire the switch, or you can use an aftermarket switch wired to the ac switch input on the ECU.

[aceman187443]

OK, is that a 12v positive OR negative input by default?

[Spunkster]

It is a 12V input, not ground.

[aceman187443]

That information is incorrect, it is -12 volt (ground) by default, inverted it is +12 volt. Good it has the option to invert input or i would have been running another wire from the engine bay.

[Spunkster]

Inverting does not change the polarity. It just changes if the button pushed is on, or off.