cat5cable

Hey guys/gals

I have fitted an aftermarket rev counter/beeper but I need to find the rev/pulse wire, now I know it says plug A Pin 19 Blue wire but when I got my ecu or ecm out of the footwell my plug A Pin 19 is a red/green and is not rev/pulse wire.
I have read other threads re beeper install but all mention Blue wire so as my old car is a 1999 can anybody point me in the right direction please.

Ginger

cat5cable

Bump

cat5cable

ok found it so after all it was a blue wire but previous owner had used it and put heat shrink black over it, so its now connected but it reads approx half ie at tickover original reads 1000 rpm aftermarket reads 500rpm and as revs climb 6000rpm aftermarket clock reads 3000rpm.

so is there such thing as a rev counter fix ??

ginger