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HELP!! '04 LS430 Mark Levinson sub not working - but the sub itself works
I posted about this a few weeks ago... but about a different question. I have an '04 LS430 with ML that the sub randomly stopped working in. It's an aftermarket Polk DB840DVC that sounded decent previously until it died. I called United Radio (rebuilds ML amps) and described the problem to them before I sent the amp to them. The technician I spoke with explained that that the ML amps never fail in the way that I described... the volume control still works, all other speakers, fade/balance controls, no door speaker pop when I turn the car on/off.... but the subwoofer doesn't work anymore. The technician basically guaranteed that the sub itself had blow/quit working.
So I ordered a Polk DB842DVC (the 840DVC is discontinued and the 842DVC is the replacement for it). The stereo shop where I brought the 842DVC to be wired evaluated the original 840DVC and noted that the impedance was still within spec and that the physical movement was still smooth. They brought it into a room and hooked it up to an amp and verified that it still functions, with me as a witness.
It's worth noting that when I went to pull the original to me 840DVC, there was still a small amount of power supplied to the sub. As I was working on pulling the sub out, I had the stereo on low-medium volume and noted that there was still a very small amount of signal being fed to the subwoofer, but it was far too quiet of a signal to be heard from the driver's seat.
My question is.... is there a fuse in the trunk area near the amp that supplies the sub independently that could be causing my lack of bass problem??
My ML system sounds amazing and it's absolutely killing me to not have my subwoofer functioning. The sub is responsible for about 100% of the bass and about 50% of the mids as far as my ear can tell... please help!!!!
The ML amplifier is powered by a 30A fuse, which drives all audio output channels. In other words, the audio output signals are not fused individually.
You had already mentioned that both the amplifier and the subwoofer are functional. The only thing else to check would be the wiring harness that goes between these 2 pieces of equipment, which would include the electrical connectors (look for corroded pins) or pinched/broken wires (look for cut wires or broken insulation that allows the bare copper to ground to metal).
I am not sure what the ML wiring look like, so take this with a grain of salt.
If I am the one who doing the troubleshooting, I would use a new wire, and connect the amp to the speaker with this wire. If this works, I would run a new wire to the back of the car to where the sub is. Just personal preference, but I rather run new wire instead of trying to figure out where the old wire is broken/pinched.
I am not sure what the ML wiring look like, so take this with a grain of salt.
If I am the one who doing the troubleshooting, I would use a new wire, and connect the amp to the speaker with this wire. If this works, I would run a new wire to the back of the car to where the sub is. Just personal preference, but I rather run new wire instead of trying to figure out where the old wire is broken/pinched.
If you decide to take the route suggested by BCT, here is sketch of the connector (at the back of the amplifier) and the 2 wires that carry the output signals to the subwoofer...
If you decide to take the route suggested by BCT, here is sketch of the connector (at the back of the amplifier) and the 2 wires that carry the output signals to the subwoofer...
Thank you!
I guess it might be worth my time to try to trace the wire from the amp to the sub and check out all of the connectors, which I'm hoping couldn't possibly be that difficult since the two components are so physically close to each other. I assume I will be able to access all of the wire(s) from amp to sub from inside the trunk? If so, I figure that I'm going to have to remove or at least peel back a large portion of the trunk lining to do that... can anyone give me some input on that part of the job? Is it a continuous wire/set of wires from the connector at the back of the amp all the way to the sub? Or are there other junctions/connectors between the sub and amp?
Please take a look at the attached PDF's and see if they are helpful. I would suggest to take your sub-woofer to the trunk and run a section of wires from it to the amplifier.
My sub hasn't worked since I got the car. I realized that the only time it does is after the car has been sitting in the sun long enough to get hot. The best answer I've stumbled upon is that there's a hairline crack somewhere in the connection and when it's heated and expanded there's a good enough connection to power the sub. I haven't spent any time looking into it because I figure once I've got time to pull the factory sub out to check it out I might as well replace it with an aftermarket.
My sub hasn't worked since I got the car. I realized that the only time it does is after the car has been sitting in the sun long enough to get hot. The best answer I've stumbled upon is that there's a hairline crack somewhere in the connection and when it's heated and expanded there's a good enough connection to power the sub. I haven't spent any time looking into it because I figure once I've got time to pull the factory sub out to check it out I might as well replace it with an aftermarket.
Replacing with aftermarket may not be the best idea if your factory ML sub is still working (sans the intermittent connection issue). It's a hotly debated topic, but the factory sub is designed for open air applications (sub not mounted in a box). There are only a few replacement subs that are reasonably inexpensive and will have the correct impedance to match up with our wonky ML system. The aftermarket sub that's generally accepted as a decent replacement is the Polk DB840DVC and is what's in my car (previous owner replaced the ML sub even though it just needed a $30 re-cone job). It's less than $100 and has dual 4 ohm voice coils that need to wired in series to result in an 8 ohm load for the amp. This sub has been discontinued and the DB842DVC is the replacement for it. The specs are very similar. Some say that the Polk sub works a little better than the original ML sub, others say the opposite. Either way, it takes all of about 5 minutes to gain access to the sub to replace it, so even if the factory sub's cone starts to separate if you decide to leave the factory sub in place after solving your wiring issue, you won't have to put a lot of effort into getting to it again.
If you do decide to replace with an aftermarket sub, a lot of people have mentioned improved performance after using sound deadening material like Dynamat or Kno Knoise to cover up the 5-6 small holes cut out in the rear deck where the subwoofer is mounted.
When you decide to investigate your intermittent sound/wiring issue, please post about it or send me a PM. I don't know when I'll get around to trying to solve my wiring issue, so if you do yours before I do mine, I'd be interested to know what you found out and what exactly was involved. Similarly, if I end up being able to investigate mine this Tuesday like I'm hoping I'll be able to, I'll post in this thread with the results.
So I got it working again... but I don't know exactly how. I do have a pretty good idea, however. Two days ago with the help of a friend, we peeled back the trunk lining on the passenger side to unbolt and remove the amp and trace the wire from the amp to the sub itself. We were unable to trace a small portion of the wire between the trunk wall and where the wire comes into the rear deck, but what we could see looked fine. I was at a loss as to where to go from there, so I decided to plug everything back in and test it with the amp not bolted back in place and just sitting on the floor of the trunk. Much to my amazement and surprise, it worked! We bolted the amp back in place, and as my friend was reconnecting the plugs to the amp he noticed something and called me over. He had peeled apart (with very little effort) a portion the sheathing that encases the 4 speaker wires that power the sub, about 1-2" from where the wires terminate into the connector that plugs into the amp. In the same exact area of this black sheathing where he was so easily able to pull it apart, he found black electrical tape wrapped around the wires. I know there's no way that Lexus/Toyota wrapped a splice with crappy black electrical tape at the factory, and that someone had previously spliced this. I'm fairly confident that this splice is why I was getting such little signal to the subwoofer. Out of the few dozen individual strands of wire inside those 4 speaker wires, I'll bet that only a few were actually touching and carrying signal. If the sub ever stops working again, or working at 5% power like it was before, I'm just going to cut out the spliced section of wires and do a proper butt-connector splice and shrink it. Shoddy splice job pictured below:
Thank you to everyone that helped me with my very annoying problem!
06-10-18, 10:40 PM
HELP!! '04 LS430 Mark Levinson sub not working - but the sub itself works
