The scheme looks similar to my '67.

On the '79 diagram, the upper half of the fusebox consists of circuits that only get power when the keyswitch position is in run or accessory.
I can not make out exactly which feed connects to the turn signal.
It is probably one of the 'Accessory' feed wires, Q1A or Q2.

The lower half of the fuse box is always hot. The hazzard flasher gets a dedicated wire direct from the battery (F38). Older cars (and prob trucks) just use a shared buss bar in the fusebox.