just had this very issue with Saffy
my converter chip was behind my clocks and all 5 wires were connected

i had Vtec in first and the 112mph limiter off
we worked out that:
Red= Live
Green= Earth
Blue= Speedo In
Yellow= Speedo out
Grey = had been run all the way across the dash and dropped down to the ECU

it was spliced into a Orange/White that was Speedo Sender wire

this may have been the ghetto fix for Vtec in first
it was what buggered me up fitting EL dials for 2 years

now have UKDM EL's in the nasty JDM KPH Analouge dials out and the converter in the bin
