Smell is the third sensory sign of alternator trouble, and it comes from the fact that your alternator is working way too hard to the brink of overheating.
Have you ever been near an electrical fire? An overworked alternator might smell kind of like that. The hot wire scent can be caused by an overheated alternator, one pushing too much power through the rotor and stator.
Or burning rubber? Yeah, that's another possibility, thanks to the rubber belt that keeps the alternator going, as well as the rubber sheaths on the wires that connect everything in your electrical system. A pulley that isn't in alignment or not turning freely will cause more friction on the belt, which creates heat and then the smell of burning rubber. If those get too hot, your nose will probably know.
Not all bad smells indicate potential alternator trouble. The aroma is distinct from other attention-worthy car smells, like the smoky sting of burning oil, the sweet stench of overflowing coolant, or the singe of overheating brakes. Of course, none of these things are good, so if you smell any of them, get them checked out. And keep in mind that the absence of a bad smell doesn't mean everything is okay. In other words, a bad electrical smell will help you narrow down the source of your trouble, but it's possible the alternator could be failing without any of these accompanying odors.
Keep reading for more hints that your alternator is on its way out.