Ground Location List

[Ron]

This is a collection of posts listing ground locations/information.
If you know of any others, please add them here.
Please start a new thread (or PM) for questions not related to the list.

"There are two connections to the frame that are especially important.
1. The battery negative cable is connected to the frame at the RH trailing arm bushing mount. The front M8 bolt fixes the cable to the frame. It must be clean and tight. That point is subject to a lot of suspension movement and the mounting bolts have a way of working loose. Not only can this be dangerous, but it will play hob with the electrics. Check these bolts as often as you check the TRBs themselves-twice a year at least.
2. The other important ground is in the front, right behind the LF wheel. The M6 bolt that fixes the LH radiator stay also connects to ground an eyelet with a number of ground wires in it. The cool fans, fuel pump, and headlights all ground at this one point, so it carries LOTS of current. It must be clean and solid.
The relay compartment is furnished a ground by a post that runs through the fiberglass bulkhead in the rear of the cabin-what would be the firewall in another car. A black cable attaches to the frame underneath the header bottle and bolts to the post, which is a piece of M8x1.25 brass stock, behind the coil in the RH front of the engine bay. This connection can become loose and really confuse a troubleshooter. As if that weren’t enough, the [+] buss is right next to it and it’s easy to encounter one with your wrench when you’re working on the other. If the battery is connected, you will know immediately when this happens. This is true from either side of the buss. Ask me how I know this.
The grounds up front go through the big connector above the washer reservoir. The current loads are so high, especially when the fans are on, that the ground positions on this connector can be melted. If there is a problem with the grounds up front, and cleaning the connection to the frame doesn’t fix it, suspect this plug. It’s so hard to get to and so tedious to work on, that going here should be a last resort."
There's one near the radiator.
There's a pair behind the rear parcel shelf wall.
There's one near the starter.
There is one ground point on the left top of the intake manifold drivers side, several black wire cluster.

UPDATES/ADDITIONS [080913]:


http://dmctalk.org/attachment.php?attachmentid=4516&d=1314390086



21098​

21097

More Info HERE (http://dmctalk.org/showthread.php?1371-DeLorean-Ground-Schematic&p=15851&viewfull=1#post15851)

[Jeff K]

This is a collection of posts listing ground locations/information.
If you know of any others, please add them here.
Please start a new thread (or PM) for questions not related to the list.

"There are two connections to the frame that are especially important.
1. The battery negative cable is connected to the frame at the RH trailing arm bushing mount. The front M8 bolt fixes the cable to the frame. It must be clean and tight. That point is subject to a lot of suspension movement and the mounting bolts have a way of working loose. Not only can this be dangerous, but it will play hob with the electrics. Check these bolts as often as you check the TRBs themselves-twice a year at least.
2. The other important ground is in the front, right behind the LF wheel. The M6 bolt that fixes the LH radiator stay also connects to ground an eyelet with a number of ground wires in it. The cool fans, fuel pump, and headlights all ground at this one point, so it carries LOTS of current. It must be clean and solid.
The relay compartment is furnished a ground by a post that runs through the fiberglass bulkhead in the rear of the cabin-what would be the firewall in another car. A black cable attaches to the frame underneath the header bottle and bolts to the post, which is a piece of M8x1.25 brass stock, behind the coil in the RH front of the engine bay. This connection can become loose and really confuse a troubleshooter. As if that weren’t enough, the [+] buss is right next to it and it’s easy to encounter one with your wrench when you’re working on the other. If the battery is connected, you will know immediately when this happens. This is true from either side of the buss. Ask me how I know this.
The grounds up front go through the big connector above the washer reservoir. The current loads are so high, especially when the fans are on, that the ground positions on this connector can be melted. If there is a problem with the grounds up front, and cleaning the connection to the frame doesn’t fix it, suspect this plug. It’s so hard to get to and so tedious to work on, that going here should be a last resort."
There's one near the radiator.
There's a pair behind the rear parcel shelf wall.
There's one near the starter.
There is one ground point on the left top of the intake manifold drivers side, several black wire cluster.

Excellent - thanks! I was going to make a post asking if anyone had this information..

[sean]

If we could start adding pictures for each ground point too it would be great!

[Jeff K]

If we could start adding pictures for each ground point too it would be great!

Yes, photos would be a great idea!

[Jonathan]

Is there a ground in behind the radio or centre console? Such as when people are discussing the ground wires from the speakers and radio?

[content22207]

There are only two places where the car body itself is grounded to the frame: the left radiator bracket and the bulkhead bolt by the coil. Every single electrical device inside the passenger compartment or under the hood (including the headlights) is grounded through one of these two locations.

Most of the engine compartment is grounded through the braided strap on the right motor mount, but not all of it (the engine compartment light is grounded through the bulkhead bolt). Tail light assemblies and and license plate lights are also grounded through the bulkhead bolt.

Bill Robertson
#5939

[BigBenb84]

Is there a ground in behind the radio or centre console? Such as when people are discussing the ground wires from the speakers and radio?

Circled in red. At least where my grounds were for the radio and stuff.

4415

[Jonathan]

Circled in red. At least where my grounds were for the radio and stuff.

4415

44374438

Hmmmm, very interesting. You can see in my pictures that I have nothing on this threaded post. I had my console apart over this past winter and I believe the only things screwed into that spot is the bracket that holds part of the console in place. Do you think there might be a secondary place the grounds go to? Or maybe my grounding wires are just buried unattached somewhere under there?

I only just this year started using my stereo a lot. I used to just stick to listening to strange noises from the car and strange noises from guys on the street (DeLorean!!). Now that I'm playing music alot, I've noticed the speakers are a POS. Now if that is a grounding issue it could explain all the crackling I hear over the music...

[content22207]

There are only two places where the car body itself is grounded to the frame: the left radiator bracket and the bulkhead bolt by the coil.

Subsequent research has revealed that almost the entire car, except for the engine and a some K-Jet devices (not the pump or ECU's), is grounded through the bulkhead bolt. There are only five devices grounded through the radiator bracket:
- Trunk light
- Windshield washer pump
- Radiator fans (2)
- Fuel tank sender
If the fans weren't so important, the radiator bracket would be a very minor concern.

Note that Dave Delman's bulkhead diagram shows the control pressure regulator grounded through the bulkhead connectors, not the engine block.

Bill Robertson
#5939

[nullset]

Where does the instrument cluster ground to?

--buddy

[content22207]

Where does the instrument cluster ground to?


4705

Bill Robertson
#5939

[nullset]

4705

Bill Robertson
#5939

Thanks. Maybe now I can get 2930's instrument cluster working….

--buddy

[Jonathan]

Can anyone confirm the stereo deck ground from my earlier post? My front speakers used to work, but of late they are not. Wouldn't doubt at all that when I had my console all apart, one of the wires might not be still connected where it i supposed to be.

Front speakers don't come on from any input; both rears come on with either FM/AM radio, or playing a cassette; only right rear speaker comes on when playing my iPod through a cassette/headphone jack adapter.

[content22207]

Speakers aren't grounded directly to the chassis. Doing that creates all sorts of feedback and noise. Speakers are grounded through additional circuitry inside the radio (thermistors?), then to the chassis.

The stock DeLorean wiring harness connector gangs all four speaker grounds together before sending them back into the unit on a single wire.

Bill Robertson
#5939

[aludden]

This is a collection of posts listing ground locations/information.
[...]
There's a pair behind the rear parcel shelf wall.
[...]


Ron, do you have more info on these? Do I have to remove the rear parcel shelf wall to get to them? How? What do they tie to?

Thanks!
Alex

[Ron]

Not really, Al, sorry....I think one may be next to/part of the bulkhead connector assy (inside right pontoon). (I can't even tell you who originally posted that to ask - I just built the list as I came across info.)

[aludden]

Not really, Al, sorry....I think one may be next to/part of the bulkhead connector assy (inside right pontoon). (I can't even tell you who originally posted that to ask - I just built the list as I came across info.)

So what's in the right pontoon? I see the harness going that direction from the relay compartment. Is it just the back of the sockets, or is there more to it? Do the ground and positive bolts by the bulkhead connectors hook up to something behind the wall, or is it just what is visible in the engine bay?

Thanks Ron!
Alex

[Ron]

Yeah, the pontoon is what all of the bulkhead connectors poke through...and the (+) jumper post...the big black fiberglass thingys that looks as if it could be the back side of a fender wells...kinda ;-) I haven't had to mess with that area. I assume the grounds for most of the bulkhead connectors join up and run back into the passenger compartment looking at Bills Ground Bus work.

What are you working on?

[aludden]

Yeah, the pontoon is what all of the bulkhead connectors poke through...and the (+) jumper post...the big black fiberglass thingys that looks as if it could be the back side of a fender wells...kinda ;-) I haven't had to mess with that area. I assume the grounds for most of the bulkhead connectors join up and run back into the passenger compartment looking at Bills Ground Bus work.

What are you working on?

I'm trying to do something similar to Bill's ground bus. The idea appeals to me, and since I have most of my interior taken apart right now, this seems like the right time. I guess there's no way to get into the pontoons, so hopefully there's nothing to see there. I will have to drill a hole through the firewall (gasp!) if I want to run a ground wire there.

[Ron]

You can get into the pontoons if you remove the board...I'm just not sure that is what he was talking about.

[aludden]

You can get into the pontoons if you remove the board...I'm just not sure that is what he was talking about.

Oh, I see what you mean. I'll check that out.
Thanks!
Alex

[aludden]

FYI,
I just removed the back panel above the parcel shelf (just remove 4 cargo net hooks) and actually there you can see the back of the bulkhead connectors, no need to get into the pontoon.

Once you do that, you see:
1. the back of the bulkhead connectors
2. a fat ground junction
3. the back of the ground bolt by the coil, which connects to the harness
4. the back of the positive bolt by the coil, which connects to the harness
5. The harness that goes to the relay compartment

So all those connections are well protected, inside the car.

7879

[john.frisina]

This is a collection of posts listing ground locations/information.
If you know of any others, please add them here.
Please start a new thread (or PM) for questions not related to the list.

"There are two connections to the frame that are especially important.

1. The battery negative cable is connected to the frame at the RH trailing arm bushing mount. The front M8 bolt fixes the cable to the frame. It must be clean and tight. That point is subject to a lot of suspension movement and the mounting bolts have a way of working loose. Not only can this be dangerous, but it will play hob with the electrics. Check these bolts as often as you check the TRBs themselves-twice a year at least.

2. The other important ground is in the front, right behind the LF wheel. The M6 bolt that fixes the LH radiator stay also connects to ground an eyelet with a number of ground wires in it.

A black cable attaches to the frame underneath the header bottle and bolts to the post, which is a piece of M8x1.25 brass stock, behind the coil in the RH front of the engine bay.

The grounds up front go through the big connector above the washer reservoir.

There's one near the radiator.

There's one near the starter.

There is one ground point on the left top of the intake manifold drivers side, several black wire cluster.

It would be great if someone could put up some pics of these points.. They're descriptive of where to find them, but I want to be sure I know what I'm looking for..

[stevedmc]

It would be great if someone could put up some pics of these points.. They're descriptive of where to find them, but I want to be sure I know what I'm looking for..

Pm me if you want Bill Robertson's email address. He has lots of pictures.

[Fluxat88MPH]

So is ther a pdf with a final complete list with pictures? That would be a great resource.

[Jonathan]

So is ther a pdf with a final complete list with pictures? That would be a great resource.

I'll take an action to draft rev 0 of that document. I don't have photos for everything yet, but let's see how it looks when I get it compiled and go from there. Give me a couple days and I'll have something for you.

[dmc4087]

Thanks. Maybe now I can get 2930's instrument cluster working….

--buddy

Would it be beneficial to take those earth wires apart and run them to the chassis somewhere?

[Bitsyncmaster]

Would it be beneficial to take those earth wires apart and run them to the chassis somewhere?

It would be hard to get at that cluster of wires on the instrument panel. I found if you just remove the inertia switch ground (just cut it off) and connect it to the frame, that will fix the problems with that ground.

[lazabby]

I'll take an action to draft rev 0 of that document. I don't have photos for everything yet, but let's see how it looks when I get it compiled and go from there. Give me a couple days and I'll have something for you.

Did you ever draft that pdf?

[Stainless]

I'll take an action to draft rev 0 of that document. I don't have photos for everything yet, but let's see how it looks when I get it compiled and go from there. Give me a couple days and I'll have something for you.

Has it been a couple of days yet ;)

If a document like this exists, I'm hoping someone can point me in the right direction. Thanks!

[Ron]

See Updates/Additions in Post #1 (http://dmctalk.org/showthread.php?1301-Ground-Location-List&p=14683&viewfull=1#post14683)

[KMC-DMC]

2. The other important ground is in the front, right behind the LF wheel.

Hi - do you have a photo of this ground?

Thanks

[Ron]

RE pm:

25070

[robvanderveer]

RE pm:

25070

from what side is this ground accessible? just remove a panel, or do i need to disassemble the entire front end?

thanks.

[Rich]

from what side is this ground accessible? just remove a panel,...?

Yes, remove the panel in the trunk, the flat one over the brake master to the left of the spare.

[robvanderveer]

Yes, remove the panel in the trunk, the flat one over the brake master to the left of the spare.
Wicked. Sometimes life can be so easy.