Phantom Voltage Problem '91 Jeep YJ

When I turn my ignition key to the lock (off) position, 12 volts remains on the accessory circuit. Even with every electrical part (radio, CB, GPS, AC Inverter) removed plus the battery cables disconnected. It will slowly bleed down to zero by itself. Or if I activate any accessory circuit, cigarette lighter, turn signal, etc, it will disappear immediately. Best I can figure is a faulty capacitor somewhere. Any ideas?

I'd suspect the ignition switch first.

But if it was the ignition switch wouldn't the voltage stay on constantly? It wouldn't bleed down to zero after 40 seconds all by itself would it? It always takes about forty seconds for the radio to bleed the voltage down.

It might. I'm curious though, is the Jeep having any other problems other than the 12V bleeding off after turning it off? You didn't mention any other issues with it, other than the 12V being on the acc circuit. Maybe that's the way it's designed?