acrmag

So I bought a 94 eg with a gsr OBD1 swap. It has a check engine light due to o2 sensor. I was reading around and it seems like obd1 should only have one o2 sensor which my car does. The wires are coming from the back of the engine the the o2 sensor goes to but the is another plug in front of the drivers side strut inside the engine bay that looks like the same plug. Does any one know what this is to? Is there anothe sensor thats not there or is this to ac or something that has been removed? Also my o2 sensor wires are all messed up and just shoved into the plug coming from the back of the engine so I ordered a new sensor.