where to tap signal for sub in 03 ml320?

Hey All I just picked up a 2003 ML320 (bought it from my friend, he sold it to me for the price the dealer was gonna give him for trade in value) which is pretty good unfortunately the Mercedes forums aren't technical, most of the posts revolve around dealers and BS accessories The car has a factory sub under the driver's seat, but it's super weak :( (not sure if it's adjustable) cause some people claim their factory Bose system has more then enough thump, but mines don't I'd like to add another amp + subwoofer under the rear seats. I've gotten the 12+ power wiring figured out, but no one (on the Mercedes forums at least) knows how to tap the signal for the new amp. I was thinking of tapping the factory sub, guessing thats the best way... also thinking of tapping the factory sub for the turn on signal for the 2nd amp anyone work or a 03 ML320 (or ML430) before? lemme know if you have any suggestions or tips thanks

Would it be "ok" to splice into one of the regular speakers? for example, the rear left speaker? would tapping into that, reduce the signal strength enough that it's noticeable?

kmn5 wrote: Would it be "ok" to splice into one of the regular speakers? for example, the rear left speaker? would tapping into that, reduce the signal strength enough that it's noticeable?

OK, I think the above would work, as my amp has LINE LEVEL inputs (so no line level converter is needed) and I can just tap the regular wires powering the speakers. If anyone thinks otherwise, please let me know thanks

you can use the rear speakers for line level inputs for that amp as long as they are full range speakers, if any of the bass is filtered out this would be a poor choice and i would recommend drawing from the subwoofer. As for the remote wire tap the ignition wire.

Thanks guys, I've located a 4 wire plug that connects to the factory Bose sub, I've tried to find out which wire colors are what, with no luck. I'll break out the voltmeter this weekend to try and figure out which are signal and what's power. And then tap off those. Hopefully I can still run the factory sub + my sub. The favtory unit is ok as a mid-bass speaker, just not as a subwoofer.