1988 Volvo 240 Left Turn Signal Does Not Work

Electrical problem
1988 Volvo 240 4 cyl Automatic 129000 miles

I just recently bought a 1988 Volvo 240 GL. When we first got it, the left turn signal was blinking fast and the bulb warning light was on. We checked all bulbs - they were all working, and we replaced two that we thought might have been burned out. After this, all of them are intact.

However, the left turn signal stops working, both from and back. When I turn on the hazards, only the right blinkers flash. When I actually engage the left turn signal, a loud buzzing noise emanates from the center panel.

I replaced the hazard flasher with a new one - same problems still emerge. Lights do not work, only the right blinkers flash, and that horrible buzzing noise happens when I engage the left turn signal. We did not check the fuses as we thought they were an unlikely culprit since the indicator lights still work, as do the internal lights and the right blinkers - only the left don't work.

Is it the turn signal switch, or is there a broken or loose wire? Any help would be appreciated.