Ignition Coil Wiring ?

[AMC86Kid]

ok so i did some voltage checks on the ignition coil two wires (yellow) - (green with white strip)

and i did not get what i thought i would see 

when the truck is off both lines are dead 

then when the truck is running the yellow wire gets 13.4 volts between yellow wire and negative terminal on battery

and the green wire gets 12.7 volts between it and the negative on battery 

 

i also checked to see where the lines run threw the main electrical harness

and they run to the master plug on the right side of the fire wall under the hood

 

 

[AMC86Kid]

so i think that the yellow is a positive line 

because it gets the same voltage as the positive post on the battery would from the alternator

but i have no clue where the green wire would be connected to 

or how is it getting the 12.7 volts  

[AMC86Kid]

Ok I took apart my main electrical firewall plug and toned out where both lines go 

 

the green one goes to the tachometer 

 

and the yellow one goes to the switch on the steering wheel for the key ignition

[AMC86Kid]

I'm assuming my stock tach didn’t work because it had a bad connection threw the main firewall plug