Grounding Electrics Clarification

[gadawg31]

Ok, just got through reading several posts regarding grounding and how important it is for the motor and interior electronics to be grounded. I just want to clarify a couple of things before I make my purchases of equipment. From what I understand is that the battery should be grounded to the frame and I can run a ground wire fromt he frame to a bus panel somewhere under the hood.

First I thought I would ground to the frame as mentioned and then add a grounding block to the firewall. Should I ground the block to the frame or run a ground wire straight from the battery?

Second, on the inside I plan on mounting another grounding block and running a ground wire to the frame on this one as well. This would allow me to run all my interior grounds to the block from the inside of my vehicle.

I have never like messing with a vehicles wires and I have all the wiring diagrams. I believe I understand the diagrams and where all the wires end up going, but I just wanted to reassure myself with advise from folks who have already been down this road before. I just don't want the lights to go out when I am driving down the dirt road. Thanks.

JD

 

[Torxhead]

All of the electrical componets on your vehicle need a return current back to the battery to operate correctly. The best way to transfer this current is from that componet thru a copper wire back to the battery negative. Using your frame which is made from steel is not such a good idea since it is a poor conductor of electricity. The CJs were built like that since it is a lot cheaper and simpler that way. That grounding block wired to the battery would be a good idea, then connect your ground wires to it rather than all of them going to the battery. I just use a brass bolt on the firewall, it connects the alternator, lights, ignition control module, head, starter relay,gas gauge, dashboard, throttle body, computer, and a few others. The starter which consumes the largest amount of current, has a dedicated cable to the battery negative from one of the starter mounting bolts. Call it overkill.

 

[Jimbos76cj]

Stud Type Junction Block - Feed-Through Panel Mount

I used one of these in my fire wall to hook my interior grounds to. It goes through the fire wall and I have a 8gauge wire connecting the other side directly to the battery. I will also run a 10 gauge wire from that lug back to the grill and use a peice of stainless althread and a few nuts to provide grounds for my grill and head lights.. Actually my head lights are grounded back to my battery but for others ive done i replace the ground with in the headlight with new longer wires that go to the SS allthread. I wil lalso run a second wire from the engine side of the above posted connector back to the rear of the frame and mount my fuel sender grouns and tail light ground.

 

[PaRenegade]

Good info in the two posts above. Just provide the most direct route back to the battery ground as possible. That's usually to a central grounding post or two. Don't rely on the body or frame for ground, paint disrupts alot of those paths. Make a copper path.

 

[IOPort51]

I made three grounding bars from 1/4x1 copper three inches long with 4 10-24 studs on one side and one on the other, the single stud is for mounting. One is on the fire wall engine side. one is on the firewall under the dash, both on the drivers side near the fuse block and one is on the fender in the back drivers side corner. The three are connected by a 16 ga wire and connected to the neg. terminal on the battery. everything ties into one of these.

There are two things that constitute the majority of problems with a CJ, wiring and vacuum. If you continue down this path of enlightenment you will good with wiring. generally if the lights are going to quit it will be in the driveway after setting for a couple of weeks, the more you drive it the better the connections seem to work.

So far it has worked well.

 

[gadawg31]

Ok, thanks ya'll. I think I have it figured out. Battery to starter ground and battery to a grounding block. From the grounding block I can connect my interior grounds to that point. I did notice that when I took the tub off, the PO had a ground to the frame for each of the rear tail lights. I could easily pigtail both these grounds and run them back through my wiring wrap up to my grounding block. Does that sound about right? Thanks.

BTW, I have a fiberglass tub, so any body grounds will not work.

JD

 

[PaRenegade]

What I did was weld a 3/8" stainless bolt to the rear of the frame to serve as ground post and additional frame ground. Then I ran a piece of LiquidTight conduit from the front to back with an 8ga. ground and hot wire and 2-12ga. wires for switching. The junction box is for relays and fuses for aux. back-up lights and a power port (cig. lighter) but it can be used for any connections. The stud with a wingnut on it now serves as a ground post for anything in the rear and it's connected right to the battery ground with an 8 ga. wire. Any ground wire should be as thick as the power wire feeding that device. (ie: 14 ga. pos. in, 14 ga. neg. out) And distance builds resistance so that's why the 8 gauge going back.

 

[Torxhead]

Ok, thanks ya'll. I think I have it figured out. Battery to starter ground and battery to a grounding block. From the grounding block I can connect my interior grounds to that point. I did notice that when I took the tub off, the PO had a ground to the frame for each of the rear tail lights. I could easily pigtail both these grounds and run them back through my wiring wrap up to my grounding block. Does that sound about right? Thanks.

BTW, I have a fiberglass tub, so any body grounds will not work.

JD

To your rear ground circut you can also add the gas gauge send unit ground to that also.

 

[AeroMoto]

I ran a grounding bus straightr off the battery to ground my interior stuff like radios and gauges. Ran an 8 gauge wire because I had some spare lying around.

When I get around to it I'm going to make a ground bus in the engine bay and the back of the Jeep. It's just a good idea to ground electronics directly to the battery. With water and mud comes corrosion, which doesn't do your grounds any favor. I chose a stud type and just used some sheet metal screws to fasten it to the drywall. Just used ring terminals on all my grounds and stacked them up and tightened them down.

 

[gadawg31]

I have heard everyone saying they are running a ground to the rear from the battery. I am hearing this correct, right? It makes sense, the more I think about it and seems a lot more reliable that bolting to the frame, but I would have never thought of it until I heard all of you saying the same thing. Maybe the tub needs to come back off and I need to do some wire plumbing. Thanks for all the great ideas.

JD

 

[PaRenegade]

Yes, that's what your hearing. I used a bolt just to create a post for attachment but since it was a bare metal frame I welded it on, which then supplied the frame with another ground source. A buss bar or even a brass post attached to the rear body will suffice as well.
Here's what I got for the front fender location to tie those grounds to. It's a side post terminal extender. But you could attach it anywhere.

 

[jdarg]

This all sounds like complete overkill to me. Even new vehicles don't use bus bars and such. I'd rather use a "stock" grounding scheme - with as few connection points as possible to do the job - than adding all of these new connections and junctions to the mix.

Run the battery to the block, then the block to the frame, and a second heavy ground from block to firewall.

Steel *is* a good conductor - as long as you take any rust down to bare metal where the actual ground wires connect to on the firewall/frame and use a new, clean toothed lock washer on the connection, you'll probably never have an issue until the wires themselves fall apart.

Frankly if it isn't broke now, and everything has a toothed washer on it and is tight, I wouldn't even mess with it unless you are bored and looking for a project.

If you are switching to glass, just run the rear grounds for the taillights, etc. to the frame (rust free around those frame holes, toothed washers), run your dash to one of the pedal mounting bolts, and the other side of the pedal mounting bolt under the hood back to the block. There's no reason to run a ground wire all the way to the rear bumper. It won't conduct as well as the frame will over that distance no matter what you use for cable. The frame has more cross-sectional area and less resistance than say 4 gauge gauge copper wire or bar.

 

[Jimbos76cj]

I like over kill. And my lights to work and be bright and not have to worry about cleaning the metal down to bare steel and for the few extra doll hairs Ill throw some extra wires at it and I like my blinkers/head lights to work right and the word and.

 

[tarry99]

Ok, just got through reading several posts regarding grounding and how important it is for the motor and interior electronics to be grounded. I just want to clarify a couple of things before I make my purchases of equipment. From what I understand is that the battery should be grounded to the frame and I can run a ground wire fromt he frame to a bus panel somewhere under the hood.

First I thought I would ground to the frame as mentioned and then add a grounding block to the firewall. Should I ground the block to the frame or run a ground wire straight from the battery?

Second, on the inside I plan on mounting another grounding block and running a ground wire to the frame on this one as well. This would allow me to run all my interior grounds to the block from the inside of my vehicle.

I have never like messing with a vehicles wires and I have all the wiring diagrams. I believe I understand the diagrams and where all the wires end up going, but I just wanted to reassure myself with advise from folks who have already been down this road before. I just don't want the lights to go out when I am driving down the dirt road. Thanks.

JD

This is a great subject since most do not understand the absolute need for proper grounding on any 12v circuit.
As most have stated a grounding block buss Bar is a good Idea..........
Frame grounding , is still in use today but due to rust, dirt & corrosion and the fact that Carbon steel is near the bottom of the list of Conductive materials its no wonder that people have gotten away from it as a method to Proper Grounding.
Modern Cars today with electronic components everywhere have common ground points that have a "Direct Path" back to the Battery.
It should also be known that the Ground Path back should be of a current carrying capacity in wire size of at least 80% of the powered circuit's carrying capacity that it's grounding.
Furthermore if the return path is of any length the wire size should be enlarged over the distance to eliminate resistance and heat build up. In fact most will measure there ground paths back in Ohm's..........shooting for the least resistance!
Also Stainless steel is lower than Carbon Steel on the list of the best metals for conductivity.......with Silver being #1 then Copper and Gold at number 2 & 3.

 

[PaRenegade]

If steel were such a good conductor of electricity why is wire made from copper? Why are electrical parts made from copper and aluminum. It's not about OVERkill, it's about utilizing the potential by improvement. The ground path is hindered by rust, paint, oil, seam sealer, and distance. It's like pinching a garden hose, it reduces the volume coming out the end. A direct copper path avoids those obstacles and transmits the currents potential. It's the same with the power side of things. AMC went the cheap route on wiring and used the smallest gauge wire it could to save money. Look at the improvement you get when you do the common headlight upgrade which basically increases the wire size and shortens the distance between the battery and the headlights.

Tarry - The reason I used a s.s. bolt was to avoid future rust. If I painted it that would defeat the purpose. The way I have it is a s.s flat washer, all the grounds ring terminals, and then another flat washer, lockwasher, and wingnut. So all the wires are touching, via ring terminals, including the 8ga. direct from the battery.

 

[74G8R2]

Acknowledging the value of good grounding, does anyone recommend replacing the entire wiring harness as part of a frame off resto? If so, what is a good source. Do any of the aftermarket harnesses use OEM wire colors so the diagrams still make since? Any success stories out there?

 

[cj7inthetwigs]

Admitting I wouldn't make a pimple on most of yalls you know what when it comes to jeep knowledge, and while I am a electrician by trade i deal with a.c. not d.c. No, I'm not a romex ranger, rather a proud I.B.E.W. member. I think the frame would work fine providing the proper steps are taken. Its really how far one wants to take it. Cooper is used for price mainly,since aluminum doesn't tolerate heat and really doesn't do well with copper mixed. I would lean towards direct lines or terminal blocks as mentioned. Didn't mean to step on any toes .

Sent from my DROID RAZR HD using Tapatalk 2

 

[cj7inthetwigs]

Well, my smartphone spell-checker likes cooper better than copper. PaRenegade, I like the detail in your system. What did you use to seal up the liqutight? Assuming its dogged off and siliconed, readers make sure when you buy yourselves some liqutight of your own you don't get sealtight instead. Sealtight has a metal jacket wound inside which means nasty business unless proper fittings are used. Makes me want to run 1/2" imc or rigid down my frame. LOL
T, as to the harness, there is another company making them other than painless and their both made in U.S.A. Theres threads on both on this forum I believe. Someone else will have to chime in on stories as im still wheelin the brittle factory harness
Sent from my DROID RAZR HD using Tapatalk 2

 

[74G8R2]

Thanks twigs, still trouble shooting mine before tear down. Exploring options.

 

[Jimbos76cj]

I use EZ wire kits for my harnesses. They are almost liek the painless kits but cost around $200 shipped. very jeep friendly. Instructions could be a little bit better but the internet will help out alot also. If you have any questions about jeep wiring I can offer some suggestions and help feel free to ask.