2004 bonneville Alternator ?
 

My daughter had the alternator replaced(voltage gauge moving and whine noise). They said the cable was melted. I think it was $200 more for the harness. As you can see it took about 10 minutes to fix the wires but my question is should there be 3 or 4 wires connected at the alternator? Maybe its a universal harness? The voltage gauge is mostly steady except when moving from park to drive or reverse it drops to 12 or 11 volts. I think that's normal but its been a few years since we had the car. I was looking at it because she said the battery gauge was moving a little and it vibrates at stop lights when she sits for a long time. I couldn't duplicate that. I found a P402 code using my Torque scanner. That code was in the history but they never mentioned it. When i cleared it about 20 seconds later the Anti Brake light came on and the Brake light with 3 or 4 fast beeps the engine did drop down too. so I cleared the codes again even though there were none and it did it again. Is that an acknowledgement the code are cleared? SE 125K

$200 for a harness? That's nuts......just need terminals B(lamp), C(field), and D(sensing)....A is not used...

P0402 is an EGR code......If the ABS light came on that is a separate problem, and do you have a scan tool capable of reading ABS codes? Not sure what those beeps are, they certainly are not some type of acknowledgement.....

Bad ground under rear seat from the battery has caused electrical anomalies like these.