The hazards work, the right turn signal works (I can hear the relay behind the glove box), but the left blinker just stays solid (along with the exterior lights).
Switch the flashers to test and then buy a new one
The flashers are the same and the emergency one never gets used
There is a chance the turn signal switch is faulty but I think you just need a new flasher
If that is true, the next step is checking grounds. These are old enough to have old care problems, and that’s a common issue. Make sure the socket is making good contact with the bulb by checking for wear, damage, and back probe for continuity.
Blinker units are cheap to replace to be sure, so do like MM007 says.