Alternator whine [Archive] - North American Grand Cherokee Association

: Alternator whine


ejschultz
10-11-2010, 07:54 AM
Could a dying alternator cause alternator whine? I've noticed in my Jeep lately that I get alternator whine. I didn't have it when I first installed my system. I can tell that my alternator is getting weaker and weaker. My headlights dim when I put my turn signal on (FML). I'm looking into some new alts right now, but I was just curious if that can cause whine.

CORUPTWJ
10-12-2010, 07:55 AM
Is the whine coming from your speakers or from the engine bay? If it is coming from your speakers, you either have a bad ground or since you said you have a system, you could have some cheap wires or your RCA wires are running to close to your power line to the amp.

But with diming lights, sounds like you are over working your alternator or your battery is going out. Stop in at AutoZone or an Advance Auto and they can run a test on your charging system and tell you if the alternator, battery or both are going bad. If you replacing one part, take it back and have them retest it to make sure the other isn't going bad too.

ejschultz
10-12-2010, 09:50 AM
Is the whine coming from your speakers or from the engine bay? If it is coming from your speakers, you either have a bad ground or since you said you have a system, you could have some cheap wires or your RCA wires are running to close to your power line to the amp.

But with diming lights, sounds like you are over working your alternator or your battery is going out. Stop in at AutoZone or an Advance Auto and they can run a test on your charging system and tell you if the alternator, battery or both are going bad. If you replacing one part, take it back and have them retest it to make sure the other isn't going bad too.

It's coming from my speakers, but only when it's colder outside. The last 2 days the weather has been a little warmer and I haven't heard it. We had some days where it was in the mid 30s in the morning and that's when I heard it. I did move wires around when I put in my new sub so I'm going to have to check and see if I crossed a power wire and a signal wire/speaker wire. I thought I was careful not to do so, but it was early in the morning when I did it so there's a good possibility that I was too tired to notice. I'm still planning on going to Autozone today to see if they will run a test on it for me. I should have some time between classes to get out there and have them do it. If either one is posing a problem, I'll probably replace both. I'd end up getting a 136 amp alternator instead of the crappy 90 amp that's on there and a good yellow top battery, possibly an Optima or maybe just a Duralast yellow top, depending on how much I feel like spending.

ejschultz
10-12-2010, 12:04 PM
And.........


The alternator failed. Good news is the battery sits at like 12.5 volts so it's good. The alternator, under a load, only charged at a steady 12.3 volts. I'm going to eventually swap that out and I'm still going to check for any crosses with my power/signal wiring.

ejschultz
10-20-2010, 08:52 AM
Ground loop isolators FTW. I got 2 Fierce Car Audio GLIs from work (BBY) and they got rid of the alt whine and a slight hum I'd get when my headlights are on. They also didn't noticeably adversely affect the sound quality of the system. I wanted to get the PAC GLIs but they're like $15 + shipping everywhere. They have an almost perfectly flat response curve from 20-20000 Hz. The ones I got look identical to the PACs and cost me less than half that for both, not just one. I'd assume they're made by pac because of their styling. There's probably only a few companies out there actually making them anyway.