Hello, my 72 turn signals work fine outside in all scenarios. With park light or lights on the dash indicators get goofy.

When park lights are on the signal indicators light up. When signals on the
indicators flash alternately inside (Dash lights are fine).
With lights one dash signals are still lit but dash lights go out. The signals
flash alternately with brights indicator lit up. I replaced switch and the dash
lights work fine but the signals still do the same thing with a new twist. With
lights on the indicators flash opposite... left indicator flashes when right is
switched on and vise versa (outside is fine). Bright switched does seem to
change anything except the lit indicators get brighter. Is it the dash circuit
board.