Where is the neg battery terminal grounded ?

Looks like my negative cable is loose down at the bottom. I ran my hand along the cable as far as I could, but It’s a gooey mess.

does anybody have a pic or can describe where the negative terminal line is bolted down ?

 

Just curious here as to what you mean about your issue. You think it's "loose down at the bottom" but you can't see where the bottom is? What exactly do you have going on with your truck?

 

Yesterday I went to turn the key, and nothing. Popped the hood & the connector on the negative terminal was loose grabbed a wrench tightened the clamp & didn’t look back.

this morning, the same thing….except now the clamp was tight, cleaned the terminal & clamp, no visible corrosion, moved the negative wire a bit (with the door open), and suddenly the key-in-the-ignition bell started dinging, moved the wire again & the dinging stopped, moved again ……

whether is a loose bottom ground or hidden corrosion seems the cable needs to be tightened or replaced.

oh, and I have the 4.7 (assume wring might be different for the 6)

 

It's grounded in several places, but the main engine grounds are at the rear of the cylinders heads, one on each side, in the back near where it mates to the transmission.

Picts here https://www.tundras.com/threads/ground-wire-replacement.37473/

 

I'd say pull both terminals and clean really well before diving deeper. I assume that the big ground cable off the battery has to go somewhere before anything is distributed but I'm not for sure where.

 

The Positive cable just runs to the starter, and the fuse box, but the ground splits like a tree trunk in the harness and goes to a bunch of places.

 

If the clamp was indeed tight, you should not have been able to easily move it even a bit.
Mind taking a picture of your battery hookups so we can have a closer look.

 

This is taken from a 2002 AC truck's exploded. Figure it may help put pics to words. This is best I can trace it from the pic, cable and how it splits is in green.

 

And honestly, I think it may extend farther, but the lines in the diagram made it hard to tell. Final termination may be as follows?

 

It does. If you look at it on the truck, it splits down at the bottom with two main trunk lines, one on each side of the engine, and one that runs up into the firewall and splits out to a bunch of places after that. Your diagram actually shows all the ground wires, but only part of it highlighted.

 

Looks similar enough to a 2/2.5 gen wiring. The wires from the battery (positive/negative/fuse box) go into a fat wire loom like this.
The ground wire from the battery (follow YELLOW dotted line) directly connects to what is circled in RED where it pops out of the wire loom and connects to the engine block:

 

On my 2000 4.7, the ground cable dives into the harness loom up top close to the battery, then emerges at the bottom of the loom near the middle / back of the engine. It attaches to the engine block down low and way in the back close to the trans on the drivers side. I replaced the original ground cable in a Subway parking lot in Yukon, OK. Well, more like bypassed it, the original is still in the loom, I ziptied the new one to the outside of the loom as the original could not be removed easily. And it’s longer than the numbnuts behind the parts counter says it is. Like 5-6’ long.

 

i’m having the same issue, i could use some advice. truck will be have no issues and then out of the blue it will act as if there is no battery at all. no dash lights, no key ding, absolutely zero when i turn the key. then randomly it will come back life and not give me no issues for another 2 weeks.

brand new battery, i’ve wire brushed terminals and made sure connections are cleaned and tight. took it to a shop and had them look at it and they really gave me no insight and said things looked fine.

seems like it has to be bad connection somewhere right?

2003 AC 4.7 4x4

 

Pretty sure this was for a/my 2000?

 

Probably have corrosion in the ground wire itself. That’s why I bypassed my original and ran a new one to the rear of the engine block. Also upgraded the battery ground to body wire with a bigger one.

 

Just wondering (because I'm no electrical engineer) why the F would you have to run it all the way back there where it's so difficult to get at?
I can make a prediction if mine ever goes bad It wont be 5-6' long

 

Where will you attach yours?

 

Anywhere a bolt up front runs into the block? I went and just peeked in there and you are right, there are not a plethora of options in plain sight.
I've been in there down to the fan bearing bracket, but I'll be the first to admit you would have more eyes on it than me.
Or I could just ground it to the aluminum

 

I re-used the factory ground point, figured they knew best.

 

Your positive battery cable is probably corroded inside the loom/sheathing. Peel it back a ways and if it’s all black or corroded or rusted looking, you may be able to get by with wire brushing it to expose good copper. Obviously, brush with the grain!

 

It's also possible @hestor has the classic problem so many others have suffered from, with cracked windshield, rotten windshield surround, or A-pillar trim/seal malfunction sending water down into the fusebox (pics & pics & pics, it happens A LOT).

While we've seen our fair share of rotten-inside power/ground cables, especially with folks that aren't wise enough to use terminal felt rings, and do zero battery terminal maintenance, and we've seen our fair share of loose/busted terminals, and even corrosion-induced shorts inside the engine bay fusebox, I always suspect the in-dash fuse block to be water-rotten these days. It'll fuck up multiple circuits and cause the symptoms he's describing, and it happens so frequently that ...

 

You mean like when they put the starter under the intake manifold?
Or created a ball joint that's geometry is constantly trying to pull itself apart?
Or made a frame that rus....... ahhh nevermind.
I LOVE MY TRUCK!

 

The ball joint thing is obviously a miss. The starter, while harder to get to, is in a position where exhaust heat can’t touch it, therefore prolonging its life to pretty much forever. Minus the copper contacts that sometimes wear out

 

Not sure if it was the original with 295k, but someone had been in under the manifold and broke the mounting bolts for the wiring harness.

 

No engine block ground, no sparky. The block acts as a ground for your spark plugs.

 

Maybe also worth noting, the bolt that holds the coil pack to the valve cover is also a ground point.

 

The back is the best point because you want the shortest path for the ground of the starter motor since that uses the most current and has the largest parasitic voltage drop.

 

I would agree.

 

My grenaded starter pinion. Did the contacts at about 110k and this happened after 250k

 

And I thought mine was mangled, holy shit