Do you mean black/yellow? If the colors are right you should have a solid yellow and a black/yellow.
The black/yellow, unfortunately is not only hooked to the alternator, but is the wire that supplies the power to the fuse box. If that's the wire you mean, you've only islolated down to 80% of the car.
If you always do what you've always done,
You'll always get what you've always got
the black wire goes to the alternator output term and the yellow wire goes to the A+term on the VR. the black wire is an ammeter shunt (very low resistance wire across ammeter term) that actually goes to a 4-way moulded rubber term block which then goes to alt output term, ammeter, S term on VR, and +12 V main buss to top of fuze block. unfortunately this main buss is distributed to ;many locations so you have not found your real problem. i suggest you put a current measuring meter between your disconnected +12 battery cable and the Battery + term and confirm your leakage current - it should be low milliamps if any. do this with key off. then pull fuzes out one by one and note if leakage decreases. if this does not eliminate leakage disconnect VR connector and note any change. then disconnect alt output term and note change. this procedure first step eliminates all powered devises, second step clears VR and third step clears alt. let us know your findings.