Dash lights blink with left turn signal

Ok - here goes.

1971 Plymouth duster.

I was wiring in my after market gauges last night by splicing into the original instrument cluster harness.

The light green wire was the only wire which got power from switching the headlight switch on - so I thought great - this is for my dash lights! Well as I was trying to figure out which wires were for the signal light indicator (found right turn easy enough). Issue came in with the left turn - the only wire which power was going on / off / on etc. to was the same light green wire which is powered up when the headlights are on.

Left turn signal works until I turn the headlights on - then it is on, but not flashing. I wired in the gauge lights (using the light green wire), and they come on with the headlights as required. With the headlights, and now dash lights on - if I activate the left turn signal, the signal lights come on and stay on (don't blink), but the dash lights blink.

Am I missing something with this light green wire being hot with the headlight switch on, and intermittent (power switches on/off/on in time with the flasher) with the left signal on.

The original temperature sender and oil pressure sender leads are not connected to anything (as I went to mechanicals), and there is an orange with yellow tracer wire that I cannot figure out what is for.

Any help or thoughts would be greatly appreciated.

Thanks,
Bryan.