I have a 67 MGB that has an Delco alternator. I converted the car to negative earth and installed the alternator. The alternator light in the tach is bright red when I turn on the key. After starting the car the light appears to be out. However, when driving the other night I noticed that the light has a slight glow. It stayed the same with or without the lights on. With the engine off I get 12 volts at the battery. With the car running I get 14.77 volts. If the alternator is charging, why does the light still have a slight glow?