Help With 1971 Dart Engine Wiring Harness

Hi, I'm installing a new engine wiring harness on my 71 dart my old harness did not have this plug on it. Can someone please let me know what it is for ? The plug is located near the ballist resistor Thanks For Your Help

For the NEW 4-prong ballist

was the harness made for an electronic ignition ? If so I agree with the above.

Yes, does it make a difference what side of the ballist resistor the plug goes on Thanks

There are two harnesses for 71 cars, early build and late build, late cars had electronic ignition and a unique harness accordingly. Every NOS harness I've seen was the electronic version even though it was only used in production for a month or so in 1971.

Mine was built in 6-71, no electronic ignition...V8 car too.