G'day Mate's

I have a WRX MY00, last of the original shape and as in Aus , I hope it will not matter much,, But question is I want to put a shift light on but need to find out the wire number and on what pin on the ECU??

And if I put a multimeter on the wire and go for a drive will it go up and down with the revs???

Is this a double post? Do be careful with that. As i answered before it is a green wire on a 02WRX. I do not think it can be measured with a voltmeter per say. I believe when i measured it ,it read 12 volts however others meaused very low voltage. You might try a search for Tach wire or similar for info on that. You should be able to tell by removing the gauge cluster.