light group wiring harness

Ignition light also needs the timer to turn it off and may need a special housing with the hole for the light to show through.
I know that circuit has been discussed here, although not certain if it was '69.

Best bet may be to find someone parting a '69 A-body with that option.
Second bet is to ask if M&H will make it.
Part number may be in the part book, more likely in the assembly drawings.