How would I diagnose a bad alternator? My truck was not wanting to start, hesitating, and performing the infamous gauge sweep. I initially thought a bad battery I bought from autozone a year ago, but I took the truck in for testing, and they said it was a bad alternator that caused the battery to fail. Is there any way this is plausible, or can be confirmed? the truck is a 2003 4WD 5.4 XLT.

 

Yes it is possible, but I would find another place to have both the battery and the alternator load tested.

I do not trust Autozone to test anything, the track record from the majority make them parts pushers.

Try a Napa or reputable service garage to have the battery and alternator load tested.

 

If its of any significance, last night as I was driving home from work, the truck began to display some strange electrical symptoms. the lights in the dasboard/headlights were growing dim and returning to normal ambience, the abs light flashed on and off once, and the radio cut in and out. could this also point to a bad alternator, or do I have some other kind of electrical issues?

I am going to have napa test the alternator today as well.

 

All symtoms of a low battery, but the battery would be low if the altenator is not recharging it.