DavidBoettcher
Nuclear
- Nov 21, 2008
- 5
A friend of mine said that if the ignition light bulb is blown then the alternator won't charge the battery. This sounds ridiculous; but I don't know enough about auto electrics to know whether it true, so I am hoping that someone familiar with this aspect of vehicle electrics can give me chapter and verse.
I'm talking about the light that comes on when I turn the ignition switch to on but before the engine is running. I know that this comes on if the alternator is not producing any output, but the suggestion from my friend is that if this bulb blows the alternator is no longer able to charge the battery. This seems ridiculous to me.
Clearly the charging current doesn't go through the bulb, because it is dark when charging. The wiring diagram doesn't show the internals of the alternator so I can't check if the ignition light has some controlling function on the alternator, but to me it would seem unlikely - I wouldn't want the important function of battery charging to be hanging off a bulb that might blow at any time.
It has been suggested to me that on older systems with dynamos and make-or-break controllers that the ignition light bulb did have some controlling effect, but that this isn't the case on more modern alternator based systems.
I'm talking about the light that comes on when I turn the ignition switch to on but before the engine is running. I know that this comes on if the alternator is not producing any output, but the suggestion from my friend is that if this bulb blows the alternator is no longer able to charge the battery. This seems ridiculous to me.
Clearly the charging current doesn't go through the bulb, because it is dark when charging. The wiring diagram doesn't show the internals of the alternator so I can't check if the ignition light has some controlling function on the alternator, but to me it would seem unlikely - I wouldn't want the important function of battery charging to be hanging off a bulb that might blow at any time.
It has been suggested to me that on older systems with dynamos and make-or-break controllers that the ignition light bulb did have some controlling effect, but that this isn't the case on more modern alternator based systems.