Melted yellow “L” wire on alternator

[danielcg]

Does anyone know what would cause the ‘L’ (yellow) wire from my alternator to melt? It was the only wire present on the plug that connects to the alt. The car is a 2002 Saturn SC2 with aftermarket audio installed, which definitely could have overloaded the alternator. But I was just wondering if something else could be wrong because I thought the current for accessories would flow through the beefier cable rather the tiny yellow wire. It may be worth mentioning that even though my alternator is not charging the battery, the charging system dashboard light does not come on after the bulb test. What is that wire even used for?

[billr]

Well, one function of that "L" wire is to turn on the dash light when the alternator output is less than battery voltage. It can't do that if it is burned out...

It sounds like the aftermarket stuff was installed incorrectly.

[OldNuc]

The alternator is controlled differently in the gen3 than it is in the older generations. The BCM turns on the light.

looking at the diagram it is likely that the "L" wire has been shorted to ground. The alternator may also be defective and the cause of the failure.

[billr]

Yep, my mistake. I should have known it was risky commenting on a gen3 when I don't have schematics that go up into those years.