Ive got a RS on my 90 F-150, dont have the second ignition hooked up and it works fine, the rear anti lock light just stays on until you turn the key on. But it will just die after running for like 5 minutes or so. Ive only noticed it with the RS cause thats the only time it idles that long. Everything stays on when the truck dies, it will restart it sometimes. Its a tachless system.