running a sub wire from battery to in the car?

Discussion in 'Electronics' started by dan@cdi, Oct 15, 2011.

  1. dan@cdi

    dan@cdi New Member

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    hi .need some help .i got a sub in my boot ready to wire up i dont no how to get the wire from the battery to inside the car and run it to the boot ?and were the earth goes in the boot ?
    thanks dan
     
  2. F1mad

    F1mad Member

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    if all goes too plan I'm doing the exact same thing this weekend mine is a 203 salon but shouldn't be too much different I'll let you know how I get on
     
  3. John

    John Hardcore MB Enthusiast

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    I wish.
    I've not done this for a long time and the last few times, I had 6 cylinder BMWs which have the battery in the boot and I used the existing wiring and just had to run the control wire through the centre of car to the headunit.

    However, last time I wired rear speakers into my previous 2004 Saab, I had to run the cables from the front speakers to the rear.

    This meant taking off the trims which are on the bottom of the door frame and running the cables along that channel under the carpet.

    I then had to remove the rear seats cushion and the carpet normally stops just under so they can be run around the exposed outer edge of where the cushion goes (often there are already cables there) and then through into the boot.

    Obviously this will vary from car to car but I imagine this is the best way. You could run the cables up the centre but you have to take a lot more trim off to access where the cables go.

    Getting cables in from the engine to the car normally means using an existing hole which has a grommet, and then finding the wire once it is poking through.

    This might be tricky given how well trimmed these cars are now - last time I did this was on a MK4 Escort in the mid to late 90s - and it was a piece of because there was a cavernous area under the dash.
     
  4. OP
    OP
    dan@cdi

    dan@cdi New Member

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    Okay thanks. Please let me no how you get on i no there should be a rubber gromit somewhere but not sure
    Thanks dan
     
  5. F1mad

    F1mad Member

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    Got the go ahead from the wife too do the install tomorrow so fingers crossed the weather is good enough
     
  6. F1mad

    F1mad Member

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    Hi just an update the only way I could find through easy enough was through the fuse box on the drivers side, I have some foam at the back of the fuse box I pushed too one side and fed the cable through into the cockpit.
    There is 2 sets of wiring looms coming out of the fuse box into the engine bay I used the one closest too the bulkhead and fed the wire through this grommet to go across too the battery hope this helps you out bud
     
  7. OP
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    dan@cdi

    dan@cdi New Member

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    That seems a bit on the hard side .but got to do it and thank you for your help . Does it sound better ?
    Wish I had bose speakers lol
     
  8. cuprastu

    cuprastu Member

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    I fitted a sub to my w202, although the boot is well insulated still makes a massive difference, with the sub going you won't worry about not having Bose!
     
  9. F1mad

    F1mad Member

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    I fitted a set of jl audio components up front and a focal 25a1 solutions sub in the boot today sounds amazing and I still have too set all the gains crossovers ect deff worthwhile all the hard work today
     
  10. OP
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    dan@cdi

    dan@cdi New Member

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    In going to have ago at running the power cable to the boot this afternoon . The fuse box is were the battery is but on the drivers side is that right ?
     
  11. F1mad

    F1mad Member

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    I said a fuse box but it's a relay box it also has the ecu in it on the drivers side
     
  12. BlackC55

    BlackC55 Authorised Forum Sponsor Authorised Forum Sponsor

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    On the 203's there is a SAM unit at the rear that has a large power cable to it. Could you utilise that?
     
  13. Doodle

    Doodle MB Enthusiast

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    Tapping into existing car wiring to get power for an audio amp is a bad idea - go direct to the battery or not at all.

    The primary fuse for the install in my E320 is over 150A - don't want that anywhere near the rest of the car systems where possible.
     
    Last edited: Oct 17, 2011
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  14. jim_bob567

    jim_bob567 Member

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    It's a long shot but if you look under the spare wheel in the boot and remove all the tools and things, there should be a rubber grommit there, i think it must be a water drain of some description in the coupe, i used it to wire in my front parking sensors. No reason why you couldn't cable tie underneath the car from the battery... post some pics if you sort it!
     
  15. Doodle

    Doodle MB Enthusiast

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    :doh:
     
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  16. John

    John Hardcore MB Enthusiast

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    I wish.
    I don't think I would personally want to run cables 'exo-car'.

    Better to run them through the car.
     
  17. F1mad

    F1mad Member

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    Hi dan
    How did you get on with your system upgrade bud ??
     
  18. effbee584

    effbee584 Active Member

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    Have done many ICE installs, always run direct power from the main battery, with an appropriate fuse in the new power line very near the battery. So that IF it has to blow, there is only a very short link left with power, less risk of fire.
    Also, as already mentioned, do not run cable under the car and up via a drain hole.
    Ideally find an existing bulkhead grommet with wires already going through. With care! use something rigid, like a screwdriver or BLUNT wire coat hanger to prod through into the footwell. Tape cable to wire and pull through. This is a delicate operation, often the bulkhead is a double construction with spaces between, and you do not want to damage existing cables.
    Once the cable is in the car, its up to you how much trouble you take to hide it, under the edge of carpets may be fine.
    From the passenger bay into the boot may well be the reverse.
    If I were you you I would figure out both routes before you start.
    It's almost certainly do-able.
    Good luck, its worth some effort for better sound.
     
  19. richard

    richard Authorised Forum Sponsor Authorised Forum Sponsor

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    The way all the rest of the cables come into the car is via any fuse/relay boxes under the bonnet. The bottom of the fusebox (or sometimes the rear) drops into the car behind the dashboard. The fuseboxes/relayboxes themselves have rubber grommets on them. Needless to say ensure that the entry of the cable into the fusebox from the battery side is really well sealed - you do not want damp ingress into the fuse & relay boxes.

    (On the SL for instance, you can come in either side, but in that case the battery is already in the boot, so rather academic)

    Richard
     
  20. jim_bob567

    jim_bob567 Member

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    What else would it be for??? :dk:
     

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