Here's the story
Last week, the audio in my truck went out. I have a 2005 Dodge ram QC
with Infnity 7 speaker system. The stereo in dash appeared to be
fine(lights, display etc), but no audio from amp behind glove box.
Took it to the dealer, they tried to replace the radio, but still no
audio. They ordered a new amp, put it in today. The dealer just
called, said as soon as they connected the new amp, it fried.
So now they are ordering a new radio, and amp.
He says for troubleshooting, they checked all my aftermarket wiring(amp
under seat for sub box under back seat). He says the wiring was fine.
He says they were able to get audio from the NEW factory stereo to
speakers by bypassing the amp.
He further claims that the old factory stereo would not pass audio to
speakers when bypassing the amp.
My question is what would cause a otherwise fine stereo to suddenly quit
and fry the amp in the process?? My concern is maybe the issue is not
originally with the stereo at all, but the pci cluster
In general but not in all cases, when you have a factory amp'd system,
you can not bypass the amp and get sound from the deck, as the deck
does not have an internal amp. Think of a home stereo system where
you have a pre-amp and an amp, same concept. So, the deck did not
"quit" working, it was most likely doing what it was suppose to, but
the amp was dead and unable to produce any sound.
How is the amp under the set for your subs wired? What was used for
ground, power, and the audio source? Did you use a line out
converter? Also, have the speakers been replaced, with what brand and
Right off though, I would say that you likely have a blown or shorted
out speaker that is causing an omh load change that the factory amp
can not handle, causing the issue you have. If you have a blown
speaker, changing the deck or/and amp WILL NOT fix the problem. The
reasons that the speaker would blow are simple but I will not get into
all that right now.
The amp under my seat is fed audio off the two front door speakers.(line
level) Power is drawn direct from battery. The ground is right at the
amp through floor boards. Speakers have not been replaced.
Risking embarrasment, Last week, I installed a new compressor (for air
horns). When I reconnected the battery, I got a 2 second wiff of
"electrical burn" I thought it was my heavily overused drill, and did
not notice the stereo not working till the next day. I have been all
over the truck trying to find the smell since it usually lingers. the
only place I can smell anything is a slight hot smell from the factory
I'm wondering if when I reconnected the battery, I managed to create a
surge big enough through the pci/pcm to toast the stereo, which then
toasted the factory amp. I have no blown fuses, there are NO dtc's
for anything showing, all my wiring checks out, as checked by me and
the dealer. Afterwards as a precaution, I did add a incandescent light
in line with my compressor relay to eat up any roaming juice when the
I would not suppose simply reconnecting the battery, should fry
anything,,, But now I'm not sure. The dealer still has my truck. They
seem to be convinced the stereo toasted itself. I'm concerend because I
play with a lot of accessories, and don't relish the idea of replacing
the stereo everytime I disconnect the battery.
Not saying that you didn't have a surge, but I would not find it
likely that a surge of this magnitude would ONLY damage/fry the radio
and/or amp and NOT do damage to any other electrical components in the
truck. I would wager that your original factory radio is fine and
only the amp is dead. The cause, more likely, though no way the only
reason it could have happen, is a blown speaker(s). Though I
definately want to hear what the dealer says.
The fact that you are running line level to your amp concerns me a
little, as though yes the front speakers produce some bass, the signal
is not that great and I would also wager that you have the bass on the
deck maxed out (assuming here). Since bass is a mono signal, here is
how you may want to run it. Get a line out converter, hook it to one
of your front speakes, both are not needed, and run a short set of
RCA's to the amp. This will allow you to turn the gain on the amp up,
the bass on the deck down and you will likely be happier with the
sound over all.
Also, if you have a lot of acc added on, you may also want to think
about adding a second battery and an isolator.
I believe I would check every place I drilled a hole on both sides of the panel
drilled. It sounds like you have shorted something in the stereo system while
installing the air horns. If you used wire ties you should check them as well,
they may be too tight causing a short. Checking each speaker to ground may also
shed some light on the situation.
The horns are not a new install,, infact nothing was changed, except the
compressor in the bed of the truck. Nothing was reouted newr wire in
But since you suggested it,,what is the proper way to check speaker
leads,,, what should ground to what, or have continuity?
With your speakers nothing should go to ground, ever. Run the + off
the amp to the + on the speak, the - to the - (for most sub set ups
and always for regular speakers) To check the omh load of your
regular speakers, in your case as you will likely have something
crossed over somewhere, you will be best off to pull each speaker and
using a DVO meter, set it at Ohms and measure it.
Please keep in mind that since you have not changed the factory
speakers out and they are (supposed to be) running off a factory amp,
there should be nothing wong with the factory speaker wiring. This
means, that to check for a blown or bad speaker, you will have to do
My first guess is a short circuit or mismatch of impedances. Also
whithout seeing the system and how you are using it there is also a
possiblty that you overheated and fried if you had it cranked a lot
for a while as those amps can get pretty hot when doing this. A
voltage spike can also wipe out some equipment if it is not internally
For a power amp to fry, the most likely cause would be that the output to
the speakers is shorted or grounded. High powered amps use a special kind of
output called bridged. None of the speaker lines can go to ground with a
bridged output. Disconnect te power amp and check the wireing. Also look for
a shorted speaker.
This saga is apparently over. I was not able to get much detail from
the dealer as to the original issue which took out the amp.
At this time the disposition is:
Dealer installed New Factory Radio, New factory amp(behined glovebox),
and everything works fine.
They state, all wiring was double checked, (stock and aftermarket), they
found no problems. They were a bit puzzled when the new replacement oem
amp fried on install. They claim after doing some research, they zeroed
in on the oem stereo. According to them something shorted out in the
head unit, and transfered itself along the pci bus to the amp
Thanks for everyones help.. I guess me nor the dealer will ever know
what caused the stereo to go, and why it affected the amp. I know they
were concerned that my pci cluster may have suffered a short, so they
were checkeing that, but it chekcs out fine.
OMg Omg,,,, I checked out the dealer work today under my dash !!!!!
They cut all the plastic out form the behind the glove box to get at the
amp, without aking the dash apart. Then scraped up all my wires, and
such. There is electrical tape on my air bag wires!!!!!!!! Looks they
scuffed them too much, and covered it up. There is even duct tape
under there hodling wires done!!!!!!!! So freaking po'd
But does anyone know the difference between the amp numbers 56043295A
and suffixe's af ae ac?
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