Fried head unit or speaker short

[sregan21]

This is a long story that happened over about a month so I am going to try to keep it short and simple.

First my subwoofers went out not sure if they're blown or not (amp still on). Next came one of my back door speakers, followed my one of my front door speakers. I was left with two door speakers until one day I started my truck and my speakers started screeching and I mean full blast worse than nails on chalkboard. Then my headunit turned off, which I fixed by replacing the radio fuse.

So I pulled the dash apart and when I took out the front RCAs the screeching stopped. I plugged in a new set of RCAs into the headunit to see if maybe the RCAs when bad some how and the screeching stopped but the music played extremely faintly turned all the way up, now only out of one of the front speakers. I plugged in a brand new subwoofer to see if the sub amp was receiving any input and nothing played, yet the amp is still receiving power.

Now in the research I have done so far, I believe I either have a short in one of my speaker components or I have a bad head unit.

I have already ordered brand new component speakers that I will be putting in soon but I am hesitant because I don't want to risk the possibility of them being blown.

Some questions I am wondering are if my headunit is fried or if I have a short could it have possibly fried my amplifiers?

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[Lasherž]

This is a long story that happened over about a month so I am going to try to keep it short and simple.

First my subwoofers went out not sure if they're blown or not (amp still on). Next came one of my back door speakers, followed my one of my front door speakers. I was left with two door speakers until one day I started my truck and my speakers started screeching and I mean full blast worse than nails on chalkboard. Then my headunit turned off, which I fixed by replacing the radio fuse.

So I pulled the dash apart and when I took out the front RCAs the screeching stopped. I plugged in a new set of RCAs into the headunit to see if maybe the RCAs when bad some how and the screeching stopped but the music played extremely faintly turned all the way up, now only out of one of the front speakers. I plugged in a brand new subwoofer to see if the sub amp was receiving any input and nothing played, yet the amp is still receiving power.

Now in the research I have done so far, I believe I either have a short in one of my speaker components or I have a bad head unit.

I have already ordered brand new component speakers that I will be putting in soon but I am hesitant because I don't want to risk the possibility of them being blown.

Some questions I am wondering are if my headunit is fried or if I have a short could it have possibly fried my amplifiers?

It sounds to me like you have a reversed polarity signal. It will be extremely faint until a song has a left to right sweep etc that makes one channel unbalanced to the other, and then since you cranked up the gain to compensate for the low volume it'll rattle your fillings and damage your equipment. Is your headunit OEM or aftermarket? Is your signal source direct RCAs from the preouts or is it an LOC?

You can test for shorts in speaker components with a multimeter which you should own anyways for setting this stuff up. A speaker will measure anywhere from 2/3 to 3/4 of the impedance value of the speaker in ohms on a multimeter. The exact number depends on the temperature. If it's OL or super low then it's a dead coil most likely. Sometimes you can also tell if the coil is ruined by gently pressing the cone downward, it will either bind or scratch if the speaker is completely toast.

As for your head unit I'm not sure, I don't have any experience with specifically how they tend to malfunction, but I wouldn't think you'd get a weak signal out, rather you'd get no signal.

Your amp can be tested pretty easy by getting a 3.5mm to RCA adapter to go into a phone or an mp3 player w/e.

I still think there's something wrong with its polarity some how if you're getting humongous bursts of noise when you don't expect it. Maybe someone else has another idea that fits better but that's my 2cents.

 

[hispls 5,000+ posts]

Now in the research I have done so far, I believe I either have a short in one of my speaker components or I have a bad head unit.

Those are indeed the two things that could cause the trouble you describe

Some questions I am wondering are if my headunit is fried or if I have a short could it have possibly fried my amplifiers?

Yes, shorting a speaker wire to ground could very well have damaged your head unit and/or amplifier. Nothing to do now but guess and test replacing things until you figure it out by process of elimination. The worry being if there is a speaker wire shorting to ground and you haven't found which one, how quickly will anything new you put in there also be destroyed when your short reoccurs? You're going to really want to dig deep or replace a lot of stuff to be safe here I'm afraid.

 

[sregan21]

It sounds to me like you have a reversed polarity signal. It will be extremely faint until a song has a left to right sweep etc that makes one channel unbalanced to the other, and then since you cranked up the gain to compensate for the low volume it'll rattle your fillings and damage your equipment. Is your headunit OEM or aftermarket? Is your signal source direct RCAs from the preouts or is it an LOC?

You can test for shorts in speaker components with a multimeter which you should own anyways for setting this stuff up. A speaker will measure anywhere from 2/3 to 3/4 of the impedance value of the speaker in ohms on a multimeter. The exact number depends on the temperature. If it's OL or super low then it's a dead coil most likely. Sometimes you can also tell if the coil is ruined by gently pressing the cone downward, it will either bind or scratch if the speaker is completely toast.

As for your head unit I'm not sure, I don't have any experience with specifically how they tend to malfunction, but I wouldn't think you'd get a weak signal out, rather you'd get no signal.

Your amp can be tested pretty easy by getting a 3.5mm to RCA adapter to go into a phone or an mp3 player w/e.

I still think there's something wrong with its polarity some how if you're getting humongous bursts of noise when you don't expect it. Maybe someone else has another idea that fits better but that's my 2cents.

I actually never touched the gain on the amplifier just the volume on the headunit. The headunit is aftermarket and my signal source is direct RCAs. I went ahead and replaced all of the speakers and the headunit and I still have an issue of only two speakers playing. I wish I would have tested the amplifier lol because that's what it's looking like to me at this point.

 

[sregan21]

Those are indeed the two things that could cause the trouble you describe

Yes, shorting a speaker wire to ground could very well have damaged your head unit and/or amplifier. Nothing to do now but guess and test replacing things until you figure it out by process of elimination. The worry being if there is a speaker wire shorting to ground and you haven't found which one, how quickly will anything new you put in there also be destroyed when your short reoccurs? You're going to really want to dig deep or replace a lot of stuff to be safe here I'm afraid.

When I replaced the speakers yesterday I noticed one speaker that had speaker connections unconnected. I have replaced the headunit as well. Now I only get audio out of the front left speaker and the back rear speaker. So at this moment of time I am wishing the amplifier was the first thing I tested because it's looking like that's the issue to me.

 

[sregan21]

Okay I found the issue. I had a spare amp laying around that I swapped out and the problem persisted, so this left me with one final thing to check, which probably should've been the first thing I check... a short in the speaker wires. Upon inspection I noticed two of my speaker wires had been chewed through, most likely by field mice (there's a million in my area).

Moral of the story, check everything before you start buying stuff!