90 Cherokee 4.0 tach wire remote start

I have been trying to program the RPM learn on my autopage 850lcd. I have discovered I tapped into the oil pressure gauge and not the tach feed. I have gone right to the coil and I find that the wire listed at the green tach wire delivers 13+ volts while the vehicle is running. This is the same at the tach gauge end. I have checked the Factory service Manual to confirm I have the right wire. My problem is the alarm install manual says I should be getting between 1-6V not the 13v+ I’m getting. Do I need to hook the tach wire to something else in the Cherokee?

Thanks, I missed the ACV part.