Alternator Whine Only When Lights Are On

[YoungExec728]

I am new to this board, but have been reading and researching from this forum for a very long time. I can't find an answer using a search so I figured I will just ask.

I don't get alternator whine in the mornings nor during the day, but once it's dark and I turn on the head lights I get alternator whine. It does not increase with volume, but does fluctuate with RPMs. I have done all the standard procedures for eliminating alternator whine (ie. RCAs away from power lines, short solid grounding, braided wires) but nothing seems to help. Again, it's only at night when I turn my lights on. Also, when I unplug my RCAs from the amp and unplug the speakers I still get that annoying high pitched sound. Any suggestions? Will a noise filter work? thanks

[KillFox]

Is it your alternator that is squealing or are you getting noise in your audio system?

[YoungExec728]

I am getting noise in my audio system. The noise is alternator whine.

[El Presidente]

Somewhere there must be an RCA by wire perhaps turning on the taillight. If you unplug the RCAs and still get it though, then Im somewhat stumped.

[jllphan]

Bad ground. Somerwhere there's a bad ground. It's probably there with the lights off, just not as intense, maybe to the point of being inaudible. With more electronics working (i.e. turning on your lights) your problem intensifies and you are left with an audible alternator whine.

Sounds like you have covered most of the basics, and while I am reluctant to recomend such, you might try a ground loop isolator. It may be that the deck may not be getting proper voltage or your amp may not be. Worse case scenario either the deck or the amp may have an internal ground problem, but not likely.

[YoungExec728]

Would you suggest an inline alternator noise filter that connects from the battery to the alternator or a ground loop isolator that connects from the deck to the RCAs?