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StalfoS 6th February 2006 06:23 AM

My amp is draining my car battery!!
My favourite people at the Volkswagon dealership spent a good 4 hours (@ ~$80/hour!!) trying to figure out why my car battery was running down, and finally they discovered that it was my monsoon amplifier. They told me that it had to be replaced, and a new unit would run me $700.

Now, it seems that thier solution to everything is to order expensive new parts. Im wondering if there is anyway to diagnose this problem, and possibly fix it, without resorting to buying a completely new amp.

I know a little bit about electronics, and am handy with a soldering iron, but I am no electrical engineer. If some of the experts at this forum could give me some ideas, or staring points, that would be awesome. It definately is the amp, because the car battery does not drain when I disconnect the unit.


Perry Babin 6th February 2006 06:34 AM

It looks like the following repair center services those amplifiers:

If you can't get it properly repaired and it works otherwise, you may consider installing a relay on the power wire. Connect the relay so that it disconnects power when the ignition is switched off.

Eva 6th February 2006 07:32 AM

Car dealers *never* repair electronics, their "technicians" are just trained to keep replacing electronic modules by new ones until the problem is solved (sometimes, good modules are replaced too).

So if you don't want to expend a whole lot of money, you have to find some smart electronics technician willing to repair it. I do that kind of work sometimes and I would be glad to try to repair that amplifier, but unfortunately I live in the opposite side of the world :bawling:

Try to find someone in your city.

MYLEY 15th February 2006 04:06 PM


StalfoS 21st March 2006 07:41 PM

Well, I found a cheap replacement amp, and guess what? The problem still occurs.

It seems to me that perhaps the head unit is at fault for switching on the amp when it is not supposed to or not switching it off. Is there any way to tell if the amp is on?

The monsoon system on the jetta seems to be a strange beast. From what I understand, the amp turns on/off automatically (or is supposed to) when it senses a signal from the HU. Also, apparently the amp is more of an active crossover than an actual amp... I think the head unit is responsible for most of the amplification.

The fact is, when I disconnect the amp, the problem doesnt occur. So any ideas why the amp is draining the battery?

Thanks again.

Stocker 21st March 2006 08:18 PM

Wires that go to any amplifier:

Input Signal(s)
Speaker Output

and the important one for you:


The remote lead from a head unit goes to a connector on the amplifier, usually near the power inputs. When the head unit turns on, the remote lead should have +12 volts on it. When the HU shuts off, the remote should go to ground potential. IF the head unit is switching the remote lead properly, the amplifier should turn on/off with the HU. Do NOT wire directly from +12V to the Remote input on an amplifier or you will....drain......the.......

jleaman 21st March 2006 08:18 PM

Is there a aftermarket head unit in this car ? Does the stereo run fine when you are driving around ? I have fixed and see this issue. It is caused buy the deck not turning the power amp off when the igntion is turned on.. to me it sounds like this..

Deck is controling the amp remote turn on. It might be possible to remove the amp's remote turn on wire and see if it still drains the power if it does then change the remote turn on wire to the ign wire. See if this helps.

DragonMaster 21st March 2006 08:26 PM


Car dealers *never* repair electronics, their "technicians" are just trained to keep replacing electronic modules by new ones until the problem is solved (sometimes, good modules are replaced too).
400$(parts and time) repair costs on a fan control that I could have removed by removing 4 screws and unplugged 2 connectors. The very bad part in this is that it only was a solder on a relay that was dried up...

bangin out 21st March 2006 11:22 PM

try a different aternator your cars battery my not be recharging and thats causeing it to die.

or you could try a capacitor.

But it could drain your battery faster than the amp does now.

DragonMaster 21st March 2006 11:26 PM

Maybe a relay on the 12v line switched by the head unit could work.

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