Left front turn signal not working

[Number1_dog]

I have a backdated 1979 911SC and the left front turn signal stoped working a week ago. only the rear one blinks.

Do I need to replace the column switch is the question.
It was replaced with a replacement unit, most likely I got a cheap one, 10 years ago, but it never self cancelled, and when I forced its return I cringed because it wasn’t smooth.
The bulb is good, I put it in the right side and it works.
I replaced the flasher relay
I looked under the dash to see if I pulled off a wire when I wired up my O2 sensors, but I didn’t find anything loose, at least what I could see.

The light unit is getting power because the running light works, and when the car is off and the left signal stalk is left on, the light turns on (is the the running light being lit?

When I turn on the right signal both rear signals blink.

Please provide suggestions.

[lindbhr]

Did you try the fuse? When this happens to me the fuse is usually good, but there is corrosion on the contacts.

[Number1_dog]

Fixed, I cleaned and replaced both front left and right turn signal fuses and it works. Thanks for the help, I’ve been loosing sleep for the last two weeks, I can now sleep soundly!

[lindbhr]

Good for you. Congrats!