Amp acting funny

[1991S13]

My system has been working fine until 2 days ago...When I turn the key usually the amp will come on at the same time as the head unit and front/rear speakers, but now the headunit and speakers come on and the amp doesn't start up for another 5 or so seconds. Then when I turn the key off the fan in the amp stays running for around 30 seconds (which the book says is normal, but it never did in the past). Is this a problem with the remote wire to the amp or could it be something more serious?

[Rex]

Amp make/model/brand?

This could be a feature of the amp called "soft (or delayed) turnon" so you don't get the THUMP at turn on. It could have started as something else changed and the amp is now delaying the turn on to eliminate the turn on thump.

I'm pretty sure the fan running afterwards is normal, but may be doing so as the amp is getting hotter?? Has anything else changed in the electrical system? If your battery/alt is getting weaker, voltage will start to drop and when it does amperage rises, which creates heat and other anomalies.

[1991S13]

My amp is a 800W Kenwood KAC-7251. Nothing (that I know of) has changed in the electrical system. But when I let it idle for a while the altenator make a chattering noise, but as soon as you rev the engine it goes away. My dad told me that could be a sign the altenator is going bad...

[Rex]

The things you're seeing can be attributed to an alt going bad. One simple thing to do, is park facing a wall at night and see ho much the lights dim at idle, or brighten when you raise the idle by giving it a little gas.Also, are you seeing the lights start to dim when sitting at idle and the bass thumping?

How old is the battery? Replacing older batteries before they die can save alt's from undue wear and tear.

Depending on your locale the current cooler weather could be adding additional load on your battery (and thusly on the alt) as well.

[1991S13]

I'll try the thing with the lights on a wall tonight. None of the lights inside or outside the car dim when the bass hits, and I live in Maryland with some f---ed up weather (we've been going from anywhere in the 20's to the 50's then back to the 30's). The more I think about it, Im thinking the alternator may need replaced. Thanks man.