If its newere is a light green wire, its gonna need a toggle. I just ground the wire and add a momentary push button to toggle it. You cant just ground newer units.

 

just installed the alpine 310 - i think
bye passed the warning screen with a relay and monatary switch - works real slick
these new units dont just need a ground or signal from parking brake but need to have them applied in a sequence in order to work
check you manual to see if it need to be applied a certain way - the alpine needed to see the parking brake -on then off - brake pedal - then paking on again.

 

momentary not monatary

 

his manual just wants the wire hooked to the e-brake, no sequencing needed.