Recently the battery light on my dash has started glowing extremely faintly, almost impossible to see untill in total darkness. Obviously this is starting to affect the performance of the battery. Problem is, the light only comes on sometimes. When the light is on, the voltage output of the alternator is reading 12.05V and when it's off it's reading around 13V give or take a bit. Could this be a fuked voltage regulator or does the alternator just need a rebuild? .