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Amp does not power on, flickers when cable disconnected.

I bought a Kenwood KAC-8403 amp a couple of months ago, and hooked it up to my car / sub. There were existing power / ground lines in the car from the previous owner. Everything worked fine until a couple of days ago when I hit a bump, and my sub and sound went out. Now the amp wont power on, andthe only time it shows any power is when I disconnect the power cord. Any ideas?

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Re: Amp does not power on, flickers when cable...

With your multimeter set to DC volts, the black meter lead on the ground terminal of the amp and the head unit on (so the amp will have remote voltage applied), touch the red lead alternately to the B+ and remote terminals of the amp. If the voltage drops below ~11 volts, you need to check the wiring feeding whichever line is too low.

Posted on Dec 05, 2007

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2 Answers

My subs/amp are not working

when you car is running, it charges the battery somewhat. So the voltage problem is not a problem. The red light means the amp is going into ''Protect Mode". This usually happens when something is wrong with the amp. Usually the amp is getting hot. Check all of you connectiong and check the final impedance of the subs. Make sure the amp can handle the impedance of the subs. If you need anymore help, message me.

Feb 12, 2010 | Kenwood Excelon KAC-X621 Car Audio...

1 Answer

Amp goes dirctly into protect

ok well it could be two thing wrong your amp dont have a good ground or your amp is a smar amp and your subs must have to be hooked up so the power from the amp cn go to the subs so the amp can see that you do have subs hooked up to take it out of protect o and look at your fuses to to smal or to big will send it to protect to

May 19, 2009 | Kenwood KAC-9102D Car Audio Amplifier

3 Answers

Adjusting wattage on kenwood kac 9103 class D mono amp

That amplifier is 900W x 1 @ 2ohms.
If your subs are 4ohm SVC wired Parallel, resulting in a 2 ohm load, each sub will only see 1/2 of the rated power. (450W ea.)
Your gain (sensitivity) setting should be between 75% and 85% to max. You will be fine.

Jan 02, 2009 | Kenwood KAC-9103D Car Audio Amplifier

1 Answer

Kenwood KAC-8401 light goes from blue to red when turned on

Either the amp is ad or the sub got shorted? You can check itby disconnecting the Sub and seeing if the amp comes on blue then. If yes, then the sub is shorted. If no, then the amp is shorted. Also chck the voltage AT THE AMP. Make sure that it is above 12 Volts.

Larry T
Winona Lake, IN

Dec 29, 2008 | Kenwood KAC-9152D Car Audio Amplifier

1 Answer

Kenwood kac-7202

Nope it's not a high-to-low level converter problem, it's most likely a problem with one of two things. 1) either you've blown the output stage in the amplifier, or 2) you've hooked up your subs wrong and your amp is seeing to low of an impedance. The amp is supposed to be 1ohm stable, but we had the same problem. When the indicator light goes red it means that the amp has gone into protection mode, now you have to figure out why. If something in the amp goes bad or just disconnects from the board it will cause power protection mode. If you fry something on the board because you are running the amp to hard or at the wrong impedance it will go into thermal protection mode, however there's no simple way to figure out which has happened.

Have you tried hooking up some different subs to see if the problem remains? try this. If the problem no longer happens then you know it's your subs, if it does still happen then you'll know it's an internal problem.

Years ago I had a Kenwood KAC-821; long story short, I melted the main power wire right off of the board, everytime I turned the system up the amp would shut down.

Take you amp to an authorized dealer and have them bench test it for you.

Let me know what you find out.

Jul 14, 2008 | Kenwood KAC-7202 Car Audio Amplifier

1 Answer


If it's only 2 months old, it should be under warranty. Have you tried to get it repaired under warranty?

Any car audio repair shop should be able to repair it.

If you want to repair it yourself, it's possible but you'd need basic test equipment and soldering/desoldering tools.

The following page shows you the basics for amp repair. Your amp is somewhat different than the one shown but the troubleshooting/repair procedure would be similar.

Basic Amp Repair Primer

May 16, 2008 | Kenwood KAC-8103D Car Audio Amplifier

1 Answer

Need help

It should be better to use the Pioneer GM-7200M Amp with your subs.

For 8 ohm setup hook up this way:
Amp out+ to Sub1 +
Sub1 - to Sub 2 +
Amp out - to Sub2 -

For 2 ohm setup hook up this way:
Amp + to Sub1 +
Sub1 + to Sub2 +
Amp - to Sub1 -
Sub1 - to Sub2 -

Nov 09, 2007 | Kenwood KAC 6201 Car Audio Amplifier

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