have a '70 1800e with aftermarket motorola alternator. First problem seemed to be voltage regulator as I was getting around 16 volts at the battery and a glowing alternator light. Swapped the regulator, made no difference- took alt to the shop and they found a bad diode. Put alt back in car and immediately noticed alt light was glowing bright, with the ignition switch OFF. The alt light went off when I started the engine. The newly repaired alt is putting out a steady 14.2 volts. I drove it a day or two and the alt light went back to normal - off when ignition was off - then it returned and whatever is causing the problem proceeded to run the battery down. I charged the battery and the alt light was back on, so I started pulling fuses one at a time and nothing made a difference. I've had the battery checked out and it checked good. One thing I did notice is when I put my foot on the brake - the light went out and stayed out, but that only worked a couple of times - lately, that makes no difference. I un-hooked the brake light switch thinking I had found something - light stays on. I've unhooked the voltage regulator - light stays on. I'm grasping . . . .