I have a 1994 Honda civic DX sedan. As the title says, my left turn signal is out. The right is fine, and it isn't the bulb. It is a small black box in the electrical wiring. I can switch it with the one on the other side and it works fine, and now that side will be out. I was wondering if anyone even knew what the heck this thing is. There is an indecipherable logo on it, but past that nothing. No part number. Just assembly dates linking it to 2004. Looks like this.






Thank you very much for your time!

 

That looks like it combies the brake and turn signal into a single bulb (instead of two in the stock system). The same sort of module is used to connect trailer lights to vehicles with a two-bulb system. You should be able to find one in any parts store. The trailer module controls both sides in one module.