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W126
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Gday all,

I own a W123 300D, and am trying to wire up an amp for a subwoofer in the boot.

Anyway, Ive already run RCA wires from the headunit to the boot successfully, and am just at a loss as to where to run the power lead from, which needs to go from the battery to the boot. If I can get it into the passenger cabin then I can do what I did with the RCAs, but any tips or suggestions?

Has anyone done anything like this before?

Cheers.
 

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84 230CE & 84 300DT
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If your battery is on the passenger side, just below the battery tray (if you're able to r...

If your battery is on the passenger side, just below the battery tray (if you're able to remove it) are the heater or A/C lines. You can pass your cable through the same rubber grommet the lines are running through the firewall. There was an extra hole not used in my car. This is the way I did it on my US model 300D. No drilling whatsoever was necessary.
 

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I'm in the U.S., so I don't know if the setup of our 300D's are different, but my batter...

I'm in the U.S., so I don't know if the setup of our 300D's are different, but my battery is located near the firewall in the rear left corner (when you look at the car from the front). Immediately to the left of the battery is a rubber "boot" through which various wires or vacuum lines run from under the hood, through the firewall, and then into the cabin. On my car, it's on the passenger side, but I imagine it might be on the driver's side in your car.

Anyway, I think it's best to go through there, or any other convenient rubber boot which has wires/lines going from under the hood to the cabin. From that hole, just stick the wire through, and then remove the under-dash panel to pull the wire into the cabin, along the outside of the seats, and then into the trunk by another rubber boot located behind the rear seat. Let me know if you have any other questions! And make sure that you run the RCA's on the opposite side of the car of any power wires you run.
 

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84 300D Euro
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Why should you run the RCA's on the opposite side of the car? Just interested because m...

Why should you run the RCA's on the opposite side of the car? Just interested because mine are together.
 

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Sometimes you can get "noise" in your system by running any power wire next to your RCA'...

Sometimes you can get "noise" in your system by running any power wire next to your RCA's. The power wire can introduce noise in the audio signal going through the RCA's, so the sound might not be at it's best.
 

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85 300 SD
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i have a question...the noise that you can get from the rca's and the power being together...

i have a question...the noise that you can get from the rca's and the power being together,is it just noise,or can you get alternator whine like that? i have a 300sd,and im having a problem with engine noise coming through my speakers...i have all my wires ran together in one bunch,and i already checked the ground to the cd player,and i think that i have good grounds for my amplifiers too,theyre bolted to the floor in the trunk...im wondering if i rerun all the rcas to the other side,if that will make any difference
 

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If you have alternator whine you might want to check the grounds that you have in the tr...

If you have alternator whine you might want to check the grounds that you have in the trunk. In my W123 I have black paint on the floor of the trunk, and you probably do too, so if you didn't already, you should sand the grounding point(s) so that it's bare metal touching your cable. If that isn't it, then I'd go ahead and try running the RCA's away from everything else. If anything, at least you'll know that the signal isn't being affected by that fat 0 gauge cable.
 

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85 300 SD
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well,i tried what you suggested,i ran my rcas for my little amp on the drivers side of the...

well,i tried what you suggested,i ran my rcas for my little amp on the drivers side of the car,and theres virtually no noise now...i guess i was getting feedback from the large power wire they were next to...thanks,wsad...you saved me some money,because my next step was buying a ground loop isolator,and that wouldve been useless...thanks again.
dave
 

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I'm glad I could be of some help. You're car looks sweet so it oughta sound good too!...

I'm glad I could be of some help. You're car looks sweet so it oughta sound good too!
 
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