ignition warning

[spatz]

one quick question, Sven from Germany told me that the ignition warning has to be connected
otherwise the alternator would not charge the battery ?
I do not know the internals of an alternator, but the output brown/yellow is a negative one and would connect to ground and fire the ignition warning light as indicated in the loom diagram, so I wonder if it is really necessary ?

[Steve_D]

spatz said:

one quick question, Sven from Germany told me that the ignition warning has to be connected
otherwise the alternator would not charge the battery ?
I do not know the internals of an alternator, but the output brown/yellow is a negative one and would connect to ground and fire the ignition warning light as indicated in the loom diagram, so I wonder if it is really necessary ?

No, the ignition warning light is not earthed.
It is powered by the ignition switch and earths through the alternator when the engine is off. When the alternator is charging then there is +12v on both sides of the ignition light so it does not light.

You need the ignition light as the 12v 'stimulates' the alternator to start charging.

Steve

[GTRCLIVE]

It all depends on what Alternator you have and how many connections are on the back. Yes the older versions did need a light, but most modern versions now have inertia switches to break the connection when the engine is stopped. (otherwise the alternator turns into a motor and drains the battery)

[spatz]

yes that was one idea that there is 12 v present through the bulb resistance but would require a high impedance of the alternator connection, will wait for the alternator to arrive and then see what is going on, thanks ! in any case a resistor should be as well as effective, as the digidash has its own circuitry to monitor the voltage.

Edited by spatz on Sunday 31st May 19:39