Sub Woofer Draining Battery When Car is Not Running

[Mark McW]

2003 Explorer XLT, Mach 6-CD stereo with factory sub woofer....

Have traced a 0.75A current draining the battery 24/7 when car is not running to something related to the stereo sub woofer.

First, I noticed the sub was not working when the stereo is playing. Then noticed when car engine starts up...the sub pops noticeably somewhat loud....once. When you shut the car off, same popping sound, but it's three quick pops. Then my battery went dead after sitting a week and the AAA guy came out to jump me measured a 0.75 amp current drain with car off......

When you charge the battery you can hear the 60 cycle hum coming thru the sub woofer, with car and stereo off. If the car sits for more than 3-4 days, battery is drained and won't start.

It's intermittent...as it did all this for several months...then everything was fine for a week or two, and now it's doing it again. Very odd. I'm pretty sure the draining of the battery measured at 0.75 amp is related to the sub woofer popping.

Has anyone seen this before? Problem with the 2 DIN unit in the dash or the sub amp shorted out to 12V? Where to start looking for the issue?

Pretty confused...

Thanks

Mark

 

[Bruces expo]

Seems to be a Head Unit Or amp issue , the sub will only get power or make noise from the head unit to the amp , have you tried disconnecting the amp and seeing if it had the same draw with the amp disconnected ?.

 

[Mark McW]

Thanks for the reply.

I have not done any trouble shooting just yet. When I park at the airport for 2-3 days or more, I simply disconnect the battery....LOL.....

I was thinking maybe the easiest thing to do in trouble shooting process is first pull the fuse for the stereo system. Just to verify for sure it's the stereo pulling the current. Looks like Fuse #3 in passenger compartment under steering wheel per manual. I was hoping to find a separate fuse for the sub woof amp....but does not appear to be a separate fuse for just this part of the stereo system. It says Radio/Amp/DVD (I have the 6 CD stereo only, no DVD).

I really don't relish the thought of removing the interior rear passenger quarter panel to get to the amp.

So, next I was thinking about pulling the 6 CD 2 DIN unit on the dashboard....much easier to do. Someone was telling me about a "blue wire" that turns the amp on/off. If the voltage on this "blue wire" is latched on always, then the amp being always on makes sense.

Again, many thanks and I will post more when i have new results.

Mark

 

[Bruces expo]

The blue wire you were told about is simply a remote turn on wire , it sends 12V source from the head unit to the amp to tell it to turn on , it should only turn on if the head unit is turned on , Also , You will probably not have that wire seeing as your all stock/factory and they do not use common colors that are used in car audio , I understand the want to not want to remove the rear panels to get to the amp , Just unsure of any other way to see if the amp is turning off or not with out using a Digital Multi Meter on the input wiring and cycling the key off and on to check the voltage , maybe someone else with factory audio knowledge will chime in , I know more so about After Market Car stereo and video than stock/factory .

 

[KORDemon7]

I believe Ford uses an audio signal to switch the factory amp on or off.