Grounding question

[DatKat933]

I'm sure everyone is tired of questions about grounds, so I will apologize now. I have a 79 K10 fleetside which I replaced the bed on and the donor bed also has a reproduced bedside on the drivers side. Since putting the new bed on, I have not been able to get my taillights to work and I believe it is a grounding issue. I am just hoping to get some clarification on a few things since where I have the truck stored, I do not have cell reception so I need to front load information. Wiring and electrical stuff is my weakest point in automotive knowledge.

The taillight to body ground is on the driver's side where I have the brand new bed side. The bedside is black, so I am assuming there is some kind of a primer or coating over the bare metal from the factory. Do I need to take a wire brush and scuff off some of the black to get to bare metal?

In doing research on here, I see alot of mention of body to frame grounding. Does this grounding need to be an actual grounding strap or could it just be bolting the bed to the frame using the stock carriage bolts? When I had the bed off, I painted the frame with POR15 to hopefully prevent rust. Could that be preventing the bed from grounding to the frame properly? (This was a last second thought I had as I typed this).

If it needs to be a grounding strap from the bed to the frame, do I use a self tapping screw to attach to a bed rail underneath then find a hole to bolt to on the frame?

Sorry again for all the questions. I am trying to learn and really struggle with electrical work. I appreciate any help I can get.

 

[H2OnSnow]

Do you not remember finding a ground strap between the bed and the frame when you pulled the old one? Yes, you need a ground strap from the bed to the frame. No, the body mounts bolts cannot be counted on to make that connection. Most body mounts have explicit separation between the two metal parts...because that is what they are supposed to do. The body is supposed to move separate from the frame, and metal to metal contact goes against that goal. Just to run the tail lights, most any wire between the bed and frame will make it work. Yes, you need to get clean metal under the ends of that wire. Both ends, yes. Just a couple of tail lights will work with just the threads of the self tapping screw...but, more is better here; clean the frame and body to clean metal, attach the screw, coat with your preferred rust preventer after assembly.

 

[DoubleDingo]

You should also use star washers. Not saying you need to buy this kit, but you could maybe buy some star washers if you don't have some already.

https://ceautoelectricsupply.com/vehicle-grounding-kits/

 

[DatKat933]

Do you not remember finding a ground strap between the bed and the frame when you pulled the old one? Yes, you need a ground strap from the bed to the frame. No, the body mounts bolts cannot be counted on to make that connection. Most body mounts have explicit separation between the two metal parts...because that is what they are supposed to do. The body is supposed to move separate from the frame, and metal to metal contact goes against that goal. Just to run the tail lights, most any wire between the bed and frame will make it work. Yes, you need to get clean metal under the ends of that wire. Both ends, yes. Just a couple of tail lights will work with just the threads of the self tapping screw...but, more is better here; clean the frame and body to clean metal, attach the screw, coat with your preferred rust preventer after assembly.

Prefect thank you! No I do not remember finding a grounding strap when I removed the old bed, so it may have been old enough at the time that it just snapped off without me noticing.

 

[Turbo4whl]

These squares were built with two ground wires to the battery. Large (4 gauge) to the engine, (10 gauge) to the fender. Bolts are the rest, to complete the circuit.

Braided ground from the bed to the frame is the dealer professional fix. Not all trucks have this. Keep in mind, the frame also needs a ground through bolts. Anything removed, painted or rusted can loose it's factory bolt connection. Wire bolted to the engine block to the frame will fix that. The fuel tank level sensor and rear lights all need a grounded frame.

I know we are not talking about front lights, but they also have an issue if the radiator support bolts loose their ground, with their connection to the fender.

 

[DoubleDingo]

These squares were built with two ground wires to the battery. Large (4 gauge) to the engine, (10 gauge) to the fender. Bolts are the rest, to complete the circuit.

Braided ground from the bed to the frame is the dealer professional fix. Not all trucks have this. Keep in mind, the frame also needs a ground through bolts. Anything removed, painted or rusted can loose it's factory bolt connection. Wire bolted to the engine block to the frame will fix that. The fuel tank level sensor and rear lights all need a grounded frame.

I know we are not talking about front lights, but they also have an issue if the radiator support bolts loose their ground, with their connection to the fender.

You mentioning front light grounding, we watched American Graffiti on the big screen a few months back, and those old cars all had nice bright headlights, which told me good grounds.

 

[1979k10]

Ground straps are where I would pony up the money and get some nice braided straps.
Frame to engine block
Core support to frame
Cab to frame or engine block
Bed to frame

And of course a solid battery cable to frame.

Then double check all the smaller mounting grounds for the headlights and taillights.

 

[Turbo4whl]

Since we are still talking ground straps, here is the 50 cent question. Why did many older trucks come with a braided ground negative battery cable? I might be able to scrape up another prize for the first correct answer!

 

[DoubleDingo]

Since we are still talking ground straps, here is the 50 cent question. Why did many older trucks come with a braided ground negative battery cable? I might be able to scrape up another prize for the first correct answer!

Because of being 6 volt systems with a generator? Weren't the 6 volt systems higher amp?

 

[Turbo4whl]

Because of being 6 volt systems with a generator? Weren't the 6 volt systems higher amp?

Yes they were. But why the braided ground instead of rubber insulated cable??

^^^This is also another hint.^^^

 

[YakkoWarner]

Yes they were. But why the braided ground instead of rubber insulated cable??

^^^This is also another hint.^^^

Probably so you could grab onto it with a clamp when either jumpering the truck or another vehicle.

 

[legopnuematic]

Some belief of reducing static electricity or something along those lines?

I can’t recall, didn’t GM stop using braided ground cables when they departed from positive ground and 6V systems?

 

[1979k10]

Cost is the real reason.

But I think they say it had to do with interference of sensors/computers.

 

[Sad Sack]

Stupid question pus I'm ignorant, but were the braided cable solid copper?