For one thing, you should not have power at the ACC terminal with the key off. Something is obviously wrong there.
When you say "I disconnect the two rear brake lights but leave the two tailights connected.", I assume you mean you removed the jumper from one brake light to the other and the brake lights are connected separately to the turn switch. That would be right.
If the right brake light has power with the turn switch in neutral, either you have something wired wrong or the switch is a dud.
Re-check your wiring diagram to be sure you have everything where it should be.
