Need some help. No sound through speakers.

[solidhadriel]

Hey guys, I'm in a bit of an unfortunate bind here.

I installed my audio system myself in my car. It worked great for 2 1/2 years. Well, I take my car to an autobody shop to do some work on my car, and when they send me to pick my car back up, they asked if my sound *never worked*. I stared at them kind of dumbfounded, because it worked fine before I dropped it off. So we spend some there trying to figure out what's wrong, and I couldn't find anything.

So I'm coming to you experts for some help!

I'll describe my system, then what I've personally tried to diagnose first.

My car is a 2011 Mustang...

Amp: Alpine PDX5
H/U Sound Processor: MTX REQ5
Kenwood speakers x4
Pioneer Shallow mount sub

So, upon my initial inspection of the car, everything physically looked OK.

My amp had the blue light on. My sound processor (a PITA to get to) was lit up. Messing with the RCA cables near the processor created a sort of feedback you can hear in the speakers. So that leads me to believe that my amp is working as intended and is not receiving a signal from my processor.

The issue is, I don't know what to check with my sound processor. I am really fearing having to take it out and inspect the connections, as that was a nightmare of a job last time. Since my amp provided feedback, I'm assuming my ground is still good, and that its not receiving a signal. Would this be right?

Any insight would be appreciated...thanks!

 

[Osvaldo de Banfield]

Did you try to take this guy from the nape and ask him/them what they did to get the system not working?

 

[solidhadriel]

Did you try to take this guy from the nape and ask him/them what they did to get the system not working?

Yeah, I had them walk me through what they touched on the inside of the car. They had to replace a sensor module for the airbags, so he showed me what they took apart and disconnected. None of it really affects the sound system. So it makes me suspicious that maybe they pulled a wire or hit my processor just enough to cause a wire to come loose?

Audio issues are the worst.

 

[Perry Babin]

If you're using this with a portable music source, plug the source directly into the amplifier to see if it works that way.

 

[solidhadriel]

That was suggested to me by a friend, so on my lunch break, I'm going to go hit up my local radioshack and buy a aux-to-rca adapter and see if my amp is still working right...

Here's to hoping.

 

[solidhadriel]

GOOD news! (To me!) Though, I wish it were better news.

I was able to get a RCA to Aux cable at work today and test out my amp. NO issues with the amp! It was able to play music via my phone thru the RCA cables (only tested 2 channels, but I confirmed my amp is working.)

Now the bad, bad, bad news... This leads me to believe that a connection between my headunit to my sound processor is messed up or (hopefully) my rca cables to my amp are messed up (unlikely.)

Looks like I get to take apart my head unit again today and get my hands dirty. Ugh!

 

[AKHeathen]

well, if they had to replace the air bag module, then that would lead me to believe that the collision was bad enough to need welding. if that is the case, even the most minor welding, then ask them about it, and if they did anything to protect the circuits from the surges. should be about 85v spikes when welding. i use an "anti-zap" clip-on, but many just disconnect the negative from the battery, since the modules are not really cheap/available/etc from a business point, not having knocked out a processor or ecm to learn from their mistake. i'm actually going to look into building some. it may come to life after pulling the fuse on the processor and head, then letting it sit and discharge for a day.

 

[solidhadriel]

well, if they had to replace the air bag module, then that would lead me to believe that the collision was bad enough to need welding. if that is the case, even the most minor welding, then ask them about it, and if they did anything to protect the circuits from the surges. should be about 85v spikes when welding. i use an "anti-zap" clip-on, but many just disconnect the negative from the battery, since the modules are not really cheap/available/etc from a business point, not having knocked out a processor or ecm to learn from their mistake. i'm actually going to look into building some. it may come to life after pulling the fuse on the processor and head, then letting it sit and discharge for a day.

Hey, thanks for the response. Wow. I think you just nailed it on the head. There was some sheet metal that needed replacing and they did mention to me the had to do some minor welding (though this was long before I found out my sound processor was destroyed).

I went ahead and replaced the sound processor with a new JL Clarion and holy crap... It sounds worlds better!