is this the ground?

[Mordan]

it is the passenger side under the back seat.
http://www.mordan.biz/bmw/e34_mass.jpg

I need a good ground for my amp

here is the pic of my ski opening. I used my Dremel to cut the metal sheet. It is really nice opening.

http://www.mordan.biz/bmw/e34_trou_ski.jpg

[Dave M]

No idea about the ground, but nice job on the ski pass-through. Was the shape outlined in the metal?

Dave

[Ross]

The brown wire is most likely a ground but not one suitable for a large draw.
If your car has the battery under the seat why not just connect there directly or to the junction point just fore of the battery?

[whiskychaser]

The body of the car is all ground. So you can pretty much pick your spot as long as you clean the paint off. But it might be easier taking it direct off the battery as Ross suggests, particularly as you are going to need a positive feed too

[tim eh?]

NO! that black box with all the red wires is B+ power straight from the battery. Do not ground to that!!!!!

There is a good grounding point right next to it- all the brown wires in this photo.
http://www.bimmernut.com/forum/attachment.php?attachmentid=6320&stc=1&d=1227449422

edit again - there is no negative in that black box, it is all positive. the fusible link is a little further down, kind of a lump on the red wire. you can take power direct from the terminal in the photo and put any fuse on it you want. 60A is a lot tho. and you don't need to fuse the ground.

fusible link -> http://www.bimmernut.com/forum/showthread.php?t=39960

[Mordan]

The body of the car is all ground. So you can pretty much pick your spot as long as you clean the paint off. But it might be easier taking it direct off the battery as Ross suggests, particularly as you are going to need a positive feed too

well not. my battery is under the hood! and I only have 1.5 meter of ground cable back from the trunk.:)

you see better here

http://www.mordan.biz/bmw/e34_masse.jpg

thx for the replies already.

[Bill R.]

The later car moved the battery to that location under the rear seat.
You can use that bolt where the seat belt is fastened for a ground.




well not. my battery is under the hood! and I only have 1.5 meter of ground cable back from the trunk.:)

you see better here

http://www.mordan.biz/bmw/e34_masse.jpg

thx for the replies already.

[whiskychaser]

Looks like a fusible link. So you get your power from that and just need a ground? Mine has one just below and forward of the hole for the subframe bushing bolt. But if yours doesnt, you could put a ring on the end of the earth wire and use the seatbelt clip bolt to secure it. Its not elegant but its heavy duty and wont be going anywhere fast

[bloodyvsunday]

Id use the seatbelt, as previously stated...
It's probably your best bet, rather than anything else in that area..
my amp in the trunk is grounded to the hatch of the trunk, lol
not the greatest but whatever

[Mordan]

Looks like a fusible link. So you get your power from that and just need a ground?

ok seat belt for the ground! :) Accepted!

about the fusible link. that's a neat idea. if you are right this power link will save me some sweat! I didn't like the idea of trying to lay a wire through the cabin from the battery under the hood.
so I just put my 60A fuse very near that fusible link. I'm going to check the which is the positive cable

btw is a fuse needed for the ground wire?

[whiskychaser]

ok seat belt for the ground! :) Accepted!

about the fusible link. that's a neat idea. if you are right this power link will save me some sweat! I didn't like the idea of trying to lay a wire through the cabin from the battery under the hood.
so I just put my 60A fuse very near that fusible link. I'm going to check the which is the positive cable

btw is a fuse needed for the ground wire?
If you have a fuse on the + side you dont need one on the ground. My only concern would be pulling an extra 60 amps through that link. But dont be tempted to connect to the 'wrong' side. You dont want to risk a fire under the carpet! But as you say, its best to make sure you have the right (+) cable first:)

[bubba966]

If you're going to run a 60A circuit to power something in the car that's not factory (like an audio setup) I'd seriously run a new, separate line up to the battery for that. 60A is a lot of current, and the factory wiring of the car isn't designed to handle that kind of extra load running off one of it's circuits.

[Mordan]

If you're going to run a 60A circuit to power something in the car that's not factory (like an audio setup) I'd seriously run a new, separate line up to the battery for that. 60A is a lot of current, and the factory wiring of the car isn't designed to handle that kind of extra load running off one of it's circuits.

well my Amp manual says I should use a 60A fuse. now I only want to power a big woofer lol and 2 speakers.

what difference would that make? the red cable B+ power as pictured in the tim eh? post is as thick as the power cable I bought initially. if that cable burns, my cable will probably set the carpets on fire as well. isn't the B+ cable unused?

[Mordan]

NO! that black box with all the red wires is B+ power straight from the battery. Do not ground to that!!!!!

There is a good grounding point right next to it- all the brown wires in this photo.
http://www.bimmernut.com/forum/attachment.php?attachmentid=6320&stc=1&d=1227449422

edit again - there is no negative in that black box, it is all positive. the fusible link is a little further down, kind of a lump on the red wire. you can take power direct from the terminal in the photo and put any fuse on it you want. 60A is a lot tho. and you don't need to fuse the ground.

fusible link -> http://www.bimmernut.com/forum/showthread.php?t=39960

yea i see the ground. thx for the picture man!

if both big red and big black cables are positive. what's their purpose?

[whiskychaser]

well my Amp manual says I should use a 60A fuse. now I only want to power a big woofer lol and 2 speakers.

what difference would that make? the red cable B+ power as pictured in the tim eh? post is as thick as the power cable I bought initially. if that cable burns, my cable will probably set the carpets on fire as well. isn't the B+ cable unused?

In the pic of your car you have a thick black cable which I take to be coming direct from the battery. This feeds all the smaller red wires via the link. The concern is if you add an extra 60 amps you may risk overloading the link or the main battery cable. Red and black in Tim's photo cant be + and - as they are connected - that would be a dead short. Think of the link as an in-line fuse, albeit a big one. But to be certain, put the neg probe of a DMM to ground and touch either side of the link with the other probe. You should get battery + voltage.

[tim eh?]

yea i see the ground. thx for the picture man!

if both big red and big black cables are positive. what's their purpose?

You're welcome. One cable is the main power supply to the rear and the other connects straight to the battery. The one with the fusible link goes to the battery. The black box is just a connector in our case. You can take your + straight from there.

And it is already fused btw, kind of... the fusible link (which is just a fuse) in mine is 50A. You might want to put a smaller one on the + to your amp so you don't blow the fusible link instead. If your amp is going to pull 40A you need to upgrade some power supply stuff on the car first I think.

[tim eh?]

well my Amp manual says I should use a 60A fuse. now I only want to power a big woofer lol and 2 speakers.

what difference would that make? the red cable B+ power as pictured in the tim eh? post is as thick as the power cable I bought initially. if that cable burns, my cable will probably set the carpets on fire as well. isn't the B+ cable unused?

No the B+ powers everything in the back eg lights, amp, seats I think, windows maybe. If you blow that fusible link a whole bunch of stuff stops working. I can't imagine any amp is that demanding, but putting a 60A fuse there won't do anything because the fusible link will blow first... I'd put a smaller fuse and see what it does... worst thing you blow a fuse.

Connector is like WC says, it's just a junction post.... no fuse in mine though.