Re: Wiring issue - Any ideas??
My guess is either the red (brake sw to turn sw) wire or one of the rear stop/turn wires (yell and grn) is worn bare and shorting to ground. The brake switch is powered by the half of the headlight sw that supplies current to the cluster lights. There is a thermal breaker in each half of the headlight switch which is probably opening when the short occurs.
You'll need to remove the turn signal switch and wiring to inspect/fix it. Might be better just to replace it.