I have a 89 CRX DX with a B16A swap in it, its running OBD0 (PR3 ECU) and in the ECU pinouts/wiring diagrams on the forums its labeled under "89-92 EF8/9 SiR" But anyway, Today I printed out this diagram so I could find whats up with my wiring because my check engine light is on and my ECU is giving me a few CEL codes. According to the diagram I have 3 wires which are plugged into unused ports, and convienently enough I have 3 ports that need to have something plugged into them, but are empty. My question is, how can I find out which wire is which? I don't know, but it seems possible, that these are the 3 wires I need. Can I pull a good ol' guess n' check with them? Or should I trace them back to what they go to? Is there an electical test that I could do to find out what they are without tracing the wires back to their source? Thanks a lot, Scott P.S. The 3 wires are plugged into ports B2, B4 and B7 (according to the diagram, these are not supposed to have wires in them) The ports which are empty but need wires are A10- Pressure Regulator Cut-Off Solenoid Valve, B9- Brake Switch (what does this do?) and C8- O2 Sensor B.