Fixing a battery cable ground "flaw"

[BigLee]

So the ground battery cable on these cars is a two-piece design.
The ground from the engine block is taped up with the positive batt cable, and attaches to the chassis frame rail beneath the battery tray, right in front of the transmission mount.
The second ground cable, going to the battery attaches to another frame stud just a few inches away from the first cable attachment.
This is what I consider the "flaw" to be.
Both of these cables should be attached to the same stud for maximum conductivity and minimum current resistance.
The only reason I can see for why they separated them may be for assembly line convenience. One cable might get installed at a different point than the other one.
However, this issue can be improved for no money spent, and for less than a half hour of relatively easy work.
Of course you have to remove the battery and battery tray to get at them.
Basically, you just remove the cable to the battery, and install it on top of the cable end going to the engine. It doesn't really alter the cable effective length or positioning to the battery, since the cable ends were so close to begin with.
The only real alteration to the cables is to bend a small tab on the cable terminal from the engine side flat with a pair of pliers so that the cable to the battery can rest directly on top of it.

I cleaned the terminal contact sides with a piece of scothbright pad soaked with WD40 to make sure they have good electrical contact with each other. I then applied a bit of grease to them for anti-corrosion.
Now this mod won't make much difference in daily driving, but if the battery is marginal for some reason, it could make the difference between a successful start, or not, since the starter current doesn't have to pass through the chassis steel to get to ground now.

Top part of pic shows stock layout, bottom is modded.
Cable going to the top right is to the engine.
Cable going to bottom right is to battery.

 

[BigLee]

Just an update.
I found these short braided ground straps and added a couple of them between the stud the cables go to, and the stud left unused from this mod.
I figured it would help ensure a more solid connection to the chassis by giving it a second ground path.
As you can see in the first pic, there is a small tab sticking up that has to be bent flat or just broken off to make room for any terminal added above it.

 

[SonicAl]

Posted this in another thread, but if you find that replacing the negative cable doesn't resolve the issue with electrical gremlins (in may case, loss of power steering and traction control, no transmission shift, intermittent locking and unlocking of doors, radio failure, AC blower failure), make sure that the positive and negative screws going into and out of the under-hood fuse box are nice and tight. When I tightened the loose negative screw, my problems went away.

 

[BigLee]

I wasn't having any issues, just saw a simple improvement that could be made.
The nut you are showing to tighten, isn't that just a box attachment nut?

 

[SonicAl]

I wasn't having any issues, just saw a simple improvement that could be made.
The nut you are showing to tighten, isn't that just a box attachment nut?

That's what I first thought, but the three screws marked with a red dot in the picture are what actually hold the box in place. Underneath the arrow is a bolt and nut clearly marked as the positive battery connection. If there's a positive coming in, there has to be a negative going out. (The positive nut is also 10mm, but it was on nice and tight when I checked.)

FWIW, I did have to retighten the negative loose nut after driving for a few days, but it's still working for me.

 

[BigLee]

Well, mostly it's positive going in, and positive going out.
It's not considered negative until the current has passed through its load.
Like the starter motor, light bulbs, cooling fan, blower motor, fuel injectors, etc.
The only negative needed for that fuse block are for the relays, and that is provided by the connector plug pins on the bottom.
And that's what those 3 bolts highlighted in red are for, to hold the 3 electrical plugs onto the bottom of the fuse block.
And that tab on the back, the one you have the blue arrow on is just a box retaining tab. There is no electrical connection there.

Here is the bottom view of a Sonic underhood fuse block. You can see the 3 bolts that hold the electrical connectors in place, and that the mounting tab at the back is just plastic. No grounding can happen there.
You can also see the 2nd block attachment bolt, hidden in the lower fuse block mounting housing.

 

[SonicAl]

Well, mostly it's positive going in, and positive going out.
It's not considered negative until the current has passed through its load.
Like the starter motor, light bulbs, cooling fan, blower motor, fuel injectors, etc.
The only negative needed for that fuse block are for the relays, and that is provided by the connector plug pins on the bottom.
And that's what those 3 bolts highlighted in red are for, to hold the 3 electrical plugs onto the bottom of the fuse block.
And that tab on the back, the one you have the blue arrow on is just a box retaining tab. There is no electrical connection there.

Here is the bottom view of a Sonic underhood fuse block. You can see the 3 bolts that hold the electrical connectors in place, and that the mounting tab at the back is just plastic. No grounding can happen there.
You can also see the 2nd block attachment bolt, hidden in the lower fuse block mounting housing.

Thanks. this is very interesting and makes a lot of sense. Tightening the retaining tab has made my care work better. I suppose it could just be the overall force pushing down on the fuse box has helped better establish the grounding connection at those three other bolts? Or maybe it was the replacement negative battery cable that did the job for me.

Appreciate the insight.

 

[cook]

This may help those with electrical issues: