aftermarket radio shorting out - Ford Mustang Forum
 
LinkBack Thread Tools
post #1 of 7 (permalink) Old 04-07-2012 Thread Starter
Apprentice
V6 Member
S197 Member
 
Jstang1808's Avatar
 
Joined: Feb 2010
Location: Burlington
Posts: 119
 
aftermarket radio shorting out

So I had two subs and my amp in the trunk. Apparently the amp was over rated on power, underpowered the subs and burnt up. Being an aftermarket radio in my 2008 v6, I can the power to the accessory fuse on the passenger side. The day that the amp stopped working I took everything out, minus the radio. On that day, the fuse in the line that powers the radio started burning out.

I checked the lines and can't find a place that might be causing the radio to short out. I've been using a 10 amp fuse in the line and it had been working fine, but now it blows after just a few minutes of use. The radio workable fine during those few minutes though.

Is there something wrong with my head unit? Is it possible that it was affected in any way by what happened with the amp?

Jstang1808 is offline  
Sponsored Links
Advertisement
 
post #2 of 7 (permalink) Old 04-07-2012
GT Member
 
stars's Avatar
 
Joined: Jan 2003
Location: ...
Posts: 1,275
 
The voice coil in one or more of the four main speakers may be partially fried causing excessive currents (shorted windings). The fact that they still make sound doesnít mean theyíre not damaged. The only way to know for sure is to pull the speaker connector and measure the speaker coil resistance with an ohmmeter. Most car speakers are nominally rated for 4 ohms impedance, which means that the DCR value that the meter reads will typically be between 3 and 4 ohms (check the specs if theyíre aftermarket speakers). If the voice coil resistance starts getting down around 2 ohms you have problems and fuses may start to blow.

stars is offline  
post #3 of 7 (permalink) Old 04-07-2012 Thread Starter
Apprentice
V6 Member
S197 Member
 
Jstang1808's Avatar
 
Joined: Feb 2010
Location: Burlington
Posts: 119
 
I have an ohm meter, could you tell me how exactly I would test the speakers? Can you describe the speaker connector to me so I know what I am looking for? If I do find some sort of abnormal reading, how expensive do you think it would be to replace?
Jstang1808 is offline  
 
post #4 of 7 (permalink) Old 04-08-2012
GT Member
 
stars's Avatar
 
Joined: Jan 2003
Location: ...
Posts: 1,275
 
Just noticed you have a convertible. In that case itís easiest to pull the head unit and measure the speaker paths from the wiring harness (unplugged from the HU). If you put the HU in yourself then you should have the necessary info to determine which wires go to which speakers. If not you may have to reason it out (the HU's manufacturer may have the owner's manual online with some wiring info). The wires will add a little bit of resistance to the measurement. So if the speaker has a voice coil resistance of 3.2 ohms the wiring and connector may add another .4 ohms to that number for a total of 3.6 ohms. To use the meter set it to its lowest range (either 20 ohms or 200 ohms range, Iím assuming itís a digital meter). Numbers around 2 ohms or below could indicate a problem with that speakerís voice coil.
stars is offline  
post #5 of 7 (permalink) Old 04-08-2012 Thread Starter
Apprentice
V6 Member
S197 Member
 
Jstang1808's Avatar
 
Joined: Feb 2010
Location: Burlington
Posts: 119
 
Ok. Thanks for the information. I'll have to find the wiring guide since i put it in myself, ive got it stored away somewhere. Hopefully I can get around to it today or tomorrow.
Jstang1808 is offline  
post #6 of 7 (permalink) Old 04-08-2012 Thread Starter
Apprentice
V6 Member
S197 Member
 
Jstang1808's Avatar
 
Joined: Feb 2010
Location: Burlington
Posts: 119
 
Im sitting here in my car with my ohm meter, everything pulled out. 3 speakers read out a steady 3.9-4.0 ohms. One speaker however fluctuated between 3.5 and 4.5.

Being different from the others, does it seem to you that this would be my problem?

This being the case, would this issue be something that would have affected the signal to my subs? Because the amp powers on and all, but the subs weren't hitting which is why I assumed the problem was with the amp. (I measured the ohms from the subs and they were fine). I never noticed the amp being hot like it was burning up, but the audio installation place suggested that the amp being burnt up was the problem. I have no idea if the faulty speaker in the cab would have any relation.

and on a side note, there are two, sort of mini subs in the doors, but I don't really know anything about them. They came in the car from the factory.

http://s81.photobucket.com/albums/j2...t=IMAG0139.jpg This photo is just showing that my remote turn on it connected to the power for my radio, I'm just trying to give you any information that might be relevant.

http://s81.photobucket.com/albums/j2...t=IMAG0137.jpg This photo is of the wiring harness itself. The red and white RCA are coming from another harness that the install shop put in to send a signal to the subs in the door. Hope this helps you understand what I'm working with!
Jstang1808 is offline  
post #7 of 7 (permalink) Old 04-08-2012 Thread Starter
Apprentice
V6 Member
S197 Member
 
Jstang1808's Avatar
 
Joined: Feb 2010
Location: Burlington
Posts: 119
 
IMAG0140.jpg picture by raychell01 - Photobucket

Little update. The speaker wire that gave me the fluctuating readings went to this speaker. From the picture, you can see that they are rated at 4 ohms. So I decided to test this one right on the speaker itself and I got readings between 3 ohms and 6 ohms. So it seems that your theory of a blown speaker applies to my situation. I am going to try running the radio with this speaker disconnected.

Sorry for all the updating, just trying to keep you in the loop.
Jstang1808 is offline  
Sponsored Links
Advertisement
 
Reply

Quick Reply
Message:
Options

Register Now



In order to be able to post messages on the Ford Mustang Forum forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.

Password:


Confirm Password:
Email Address
Please enter a VALID email address for yourself, otherwise you will not receive the necessary confirmation email needed to confirm, validate and activate your new AFM member account.

Failure to provide a VALID email address, will result in the cancellation of your new AFM member account registration.

Email Address:
OR

Log-in










Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page



Posting Rules  
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are On

 
For the best viewing experience please update your browser to Google Chrome
 


Search Engine Friendly URLs by vBSEO 3.6.1