Wayne W

When I started the car this morning, an awful whine started coming from the speakers. It changes pitch with engine speed, so I'm assuming it's "alternator whine." I've had no other problems since I replaced the factory head unit about 7 months ago, so should I assume something just came loose? What's the first thing I should check?

I've got a 2005 Mustang with Shaker 500 stereo.
I don't know much about the factory amps, or whether or not they can be adjusted like an aftermarket amp.

Also, since the only thing I've done is replace the head unit, I'm assuming the power and signal wires are an appropriate distance from each other.

Henry goris

alternators aren't very expensive, it might just be broken. you could take it into advanced auto parts and they'll run a free diagnostics on your alternator for you and tell you what's up.

cobalt07

check to see if the speaker wires are running near the main power wires, they should be at least 18 inches apart

georgewillings

This has nothing to do with replacing an alternator, which is expensive considering none are less than $100 and go up to right around $700 to replace. I do not care what the MECP guide says, it has nothing to do with running speaker wire along side the power wire, I had many setups ran like that with zero problems at all. There is also no need to put a cap on your alternator, that is absolutely absurd to even contemplate.
You do need to look into getting a ground loop isolator, now this is a band aid for the actual problem, which can be a major pain in the butt to figure out. But the ground loop isolator should do the trick. Then look at your rca wires, if you used the cheap ones that could also be your problem, since the cheap ones have little to no insulation around the jack. The last thing, if the ground loop isolators do not work and replacing the rca wires do no work, then it is most often your amp. Right now I have the same problem as you. I have alternator whine and it drives me crazy, I tried replacing the rca wires, using a ground loop isolator, nothing still have the problem. One way to find out it if it is your amp that is causing the problem, turn your gain down, if it goes away it is your amp.

Scott W

find a different ground for the radio and it should go away.