I Was told by an egt tech that the white wire with the green tracer was the tach output signal, the red wire with the yellow tracer was the 12 volt power supply and obviosly the black was the ground. My Egt' work fine but i can not get the tach part to work. These wires are acutually coming off of the speedo. they then go to the tach. I have a solar powered digital tach that looks like a little calculator, it is listed with a part # in the ski-doo race manual. I can't get a tach signal off any wire with it though on the tach or speedo harness. I can however get a signal from the white wire with the blue tracer off the ignition coil. what gives? anyone have any info on this? by the way i have an 05' 800 PT. I find it wierd that the ski-doo tach works fine but my avenger doesn't and that i can't find any signal with the digital hand held tach . it has a little roach clip looking thing that clips on the wires. thank you all fo your input.