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Whats wrong with my stock AUX input?

3

3 for the money

Guest
Just bought a used '07 MS3 GT w/ Bose.
I had an 07 3S before with an AUX input so I know my MP3 player should work.

When I go to play the music only the highs come through and hardly any voice or lows.
So weird to explain but it's like the music is playing down a long hall or something.
What could the problem be?

I'm thinking the AUX recepticle has been damaged.
I've tried 2 diff cables and MP3 players.
 
mndsm

mndsm

I'M OFFENDED!
Typically when it's a signal feed issue, it's one of two things. Either the cable is bad, or the car is bad. Now you said you've tried two different cables and three audio sources- I know it sounds stupid- but have you veriified the cables/mp3's in another car? I thought for sure mine was shot, but it turned out I had a whole shitpile of crap cables. They're made cheaply.

The other option- is one of the signal wires to the preout in the back oh the h/u came loose. Since it's a used car, I'm going to go ahead and assume you don't know the entire history of it. If the h/u was ever pulled, or the center console, it could be very easy for a wire to come loose and lose some of the signal. Now what baffles me a little- is generally when that happens, you lose an entire side of speakers completely, say- the left channel. I've never heard of a low end cutout unless....


And this is something I seem to remember from my car, and it may or may not be true. I know with the Bose, the aux in signal actually has its own set of presets for balance/fade/etc. So when you swap to aux- say you have your bass @ +3, it won't carry over. And I remember the stock presets (0's across the board) sounding like garbage.

Last possible option, depending on the mp3 player used, I know some of them kick out really crap signal. Now it may not sound like ass on headphones, because headphones are designed to process a much thinner range of frequencies, and to fill out in that range, and the mp3 player could be kicking out a signal accordingly. Stick something like that on a stereo with a little power, and you're going to be exposed to a range of sounds/frequencies that may have been lost listening to it via earbuds or whatever.
 
3

3 for the money

Guest
Update:
Looking for a potential solution I hooked the MP3 player back up and noticed it was low on power. I plugged in my mini USB car charger and bam it sounded amazing (minus the ground loop squeal).
I tried multiple other sources, another MP3 player and my phone and they sounded like crap unless I plugged them in to the charger.
My thoughts:
Could there possibly be something wrong with the grounding of the AUX input?
If so where do I look to fix it?
 
3

3 for the money

Guest
Looks like I'll be tearing the console out so I can take a look at the wiring to the AUX port
 
mndsm

mndsm

I'M OFFENDED!
Yeah, it's not hard though. I saw Dan gave you the right idea. Worst case scenario, let me or someone else know, we've all torn these apart before and I'm sure we'd help.
 
S

spek1098

Guest
Got a multimeter? If not, find one, test the impedance (ohms) from the ground on the jack, it’s the first contact inside the jack, to some bare metal on the chassis. If you see anything with a K (kilo-ohms) it’s for sure a ground issue.
 
mndsm

mndsm

I'M OFFENDED!
Welp, here's an update on this. We tested various mp3 players, cords, and even went so far as to swap the aux port itself out for the one in my car. Same thing. The sound initially was as though it was cutting out low level, but as I listened to it, I'm 90% sure it's cutting a line signal, and only running it in mono instead of stereo. That would certainly explain the reduction in volume, because depending on the track, the music isn't going to be directional, it's going to be a full fill. When the mp3 player is plugged into a charging jack, and subsequently the 12v out in either the dash or in the center console, the full sound is there, but there's a LOT of interference, which I am sure is electrical. Now something that I did notice is that the 12v from the aux area and the aux port itself share the same basic wire loom towards the bulkhead of the car. Meaning, the power wires and the stereo wires are all taped into one bundle. Something tells me that there is an incomplete circuit somewhere along the way between the armrest and the dash, and that the electricity is impeding the signal, causing the mono cut out. When the circuit is completed via 12v>mp3>aux port, it allows the full stereo signal through, though the electrical is there at the same time, which is cause the ground loop-like interference. I'm sure he's got a bad ground somewhere, I'm just not sure where.
 
3

3 for the money

Guest
Alright, so if it is a ground issue what can be done to resolve it?
I will test the impedance of the jack and get back.
 
mndsm

mndsm

I'M OFFENDED!
Generally, if it's a bad ground, you've got a loose wire somewhere. Find that wire, un-loose it, and you're good to go.
 
S

spek1098

Guest
I bet there is a lone ground wire coming off the port, just tap into that with a wire and run it to the chassis.
 
Z

zero cool

Member
Somewhere between the jack and the radio the ground line is broken. could be a cracked solder connection at the jack or a problem elsewhere. the key to this is the fact that when you plug in the charger it works and sounds great minus the ground loop noise. the charger is connecting the ground line and then it works.

I HAVE a spare brand new in the box factory aux jack if you need it.
 
mndsm

mndsm

I'M OFFENDED!
It's not the aux jack itself, I know mine is good, and we swapped it into his car, and got the same issue, and plugged his into my car, and no problems. So it's the wiring itself, somewhere.
 
3

3 for the money

Guest
Great ideas guys thanks. I have just been using CDs for awhile so when I finally get to fixin the damn AUX jack I'll post what I find.
 
3

3 for the money

Guest
Wow, I never finished this thread with my findings. I found out it's got to be a bad ground in the HU. I traced the audio cable all the way to the HU and there was no break/cut in the wire. I was able to create a new ground but got a lot of alternator feedback.
 
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