Can anybody please help me troubleshoot
1997 Chevrolet Lumina. Rear left turn signal and rear left stop signal don't work.

Bulb is working.
Checked fuses - seem OK too.
Emergency flasher and night time indicator both work well (so both coils on light bulb work and wiring works too).

Thank You.

 

Looks like problem is in faulty turn signal switch. If I push it slowly at some point bulb start flashing, push it farther - light stops flashing.

Still have no clue why is stop signal affected.