turn signal issue

[crazy'boutOlds]

good day everyone.
Here's my issue.
When I turn my left turn signal on without the lights on, it blinks really slow. Just the left one.
If the lights are on, either parking or head lights, it just stays bright with out blinking.
All my bulbs are okay, the grounds look intact. Any ideas what else to look for? The right turn signal works flawlessly.

 

[tkruger]

Cheep and easy thing to try is to change the flasher unit.

 

[CWPottenger]

That sometimes is a bad socket. The bulb is finding ground through the other side of the two element bulb.