Last week it was my fuel line that took a dump, and tonight while driving home I lost a headlight, so I stop at the local auto supply, pick up a new one and when I started the engine, the check engine light comes on and I notice that the alt gauge drops down to 12 V. Fault code says alternator open or shorted field - the battery connections are nice and tight, does this always mean a bad alternator or is there a fuse link somewhere that could have opened? The alternator was working perfectly before with steady output on the gauge. Just seems like a strange coincidence that the headlight and the alternator would quit the same time.

 

yep, alternator is bad. I charged the field directly from the battery and only got the battery voltage across the terminals 12.03 V. I found a brush, bearing and diode kit online for about 68 bucks. Sure glad it's not the (very expensive) PCM. Anyway, thanks to previous posters on how to troubleshoot this.