okay, well i bought a wiring harness, and i also got a conversion from obd2 to obd1, here's the thing...after looking at the harness it only has to plugs that goes into the ECU. can this be right? there's only 1 blue and 1 gray. i'm looking at my conversion adapter and it has slots for 3 plugs. i looked at my 98 obd2 harness in my civic and it also has 3 plugs (1 small gray, the one missing from my 99-00). does the 99-00 harness only have those 2 plugs and the one green accessory plug?

 

You should have the 3 plugs, plus the green one.

 

could the 3rd plug possibly be for automatic vechicles?

 

your 98 harness is OBD2 and 99-00 is OBD2.5

96-98 has 3 plugs
99-00 has 2 plugs + 1 inside= 3 plugs

You should have bought an OBD2.5 adapter instead