So basically I tried to hook up a 900w amp the other day and blew the alternator... I guess. Car shut off and I had to get it to oreillys to get a new battery I figured mine was 4 years old. Still didn't start up without a jump and guy said I blew a diode on the alternator . So I did the big 3 , replaced alternator battery and now it starts and runs but my headlights are flickering when my rpms are low , like idling. Runs good otherwise but I don't want to hook up the amp til this is fixed and I know the alternator is good

 

Flickering headlights means that your alternator isn't putting out enough power. Is the alternator new or "remanufactured"? Also, with your Big 3 upgrade, you kept the original factory power lead on the alternator, and just added a second lead right? Could be your grounds as well. Pics would help. If you're confident that you did your Big 3 properly, go to Advance and get the free charging system check.

 

what i failed to mention is that i tightened the belt after succesfully installing the new alternator and dropped my ratchet which touched the alternator (i know im stupid for not disconnecting the - terminal) and some sparks flew but it still started. Im sure i did the big 3 properly but i removed the old + wire as it was pretty corroded and nasty. I figure 0 gauge should be just fine for + to alternator. all fuses are good to go also. i did check the voltage at oreillys once i replaced battery and alternator (after ratchet incident) and found that battery was OK but alternator at idle was low output <30 amps. the headlights are fine when revved to 2500-3000 rpms but once it drops down below 1500-2500 the lights go dim. Could it be the voltage regulator in the alternator? If so it looks like its inside the alternator and tough to get to but i'm wondering if i should just go ahead and try and replace the alternator again.

 

the alternator said brand new

 

Hopefully that alternator came with a warranty. That sounds like the problem to me, especially after those test results.