I found this disconnected. I wonder why the previous owner of the car did it ( i have had the car for a few months). I checked the manual, can't find it. It is right next to the under- dash fuse box. Honda civic 1997 EX, D16Y8 with cruise control, M/T.


It is the blue one on the right. Any idea what it is for?

 

Those look like the Honda Service Connectors, the 2 pin and 3 pin. The 6th gen (96-00) went OBD2 so has an OBD2 port but I believe Honda kept their original setup available for this generation. The 2 pin you short with a paper clip to get the blink codes if you don't have an OBD2 scanner. The 3 pin is what Honda uses to connect their Diagnostic equipment to to get live data from the car. At least that is what those two connectors look like to me. I could be mistaken as my experience is mainly with the previous generation.

 

Looks like the blue object is associated with some type of added accessory. Can you trace the wires? Where do they go?

 

It appears that the 2-pin connector has a brown wire and a light blue wire... which would suggest it is the 2-pin SCS connector plug. I noticed that the OP states that he hails from Argentina, so it is likely that even though this vehicle is a 1997, the engine management system functions more like our USDM OBD-1 style '92-95 systems.

OP, the three pin plug is used to read live data with a high end scanner like the factory HDS, Launch, Maximus or Zeus. Most people never use it.

 

It's possible. If correct, jumping the 2P connector would cause CEL to stay on steady or blink codes.

 

Agreed.