1973.5 911T front signal issue
 

Dear Porsche Person,
I've changed the left & right front turn signal housings. My issue is the front driver's side DOES NOT flash, but the other 3 signals do flash.
The possibilities: 1. Even new, the housing is defective 2. The wiring on the turn signal housing is defective or loose 3. The relay flasher is defective, which appears to be original (HELLA TBB264DB/002479-01/2(4)x21W-12V/Nichiwerieg).
I do appreciate any thoughts on what to consider as the source of the problem.
Thank You,
Kerry

You can swap the working unit with the non working unit to see if the fault is in the wiring/plug or the unit.

Check the bulb, even if it is new

The Hella flasher provides a pulsing voltage from zero to 12 volts DC to the directional/hazard circuits. If you have flashing outside directional lights and tach directional indicators except the left outside front directional light and you have swapped out the housing then your issue is after the flasher relay and turn signal switch and before connector to the wires to the left front housing. Do you have the same problem with the hazard switch selected?