Is the factory TJ frame electrically grounded to the body?

[UND_Sioux]

Funny that this came up in my feed at the bottom today. I'm setting up my Jeep to be flat towed and my brake setup requires the negative from the RV to connect to the negative of the Jeep for both the Jeep tail lights but also for a built in battery charger on the brake system. The long 4 conductor wire was going to be routed back toward the back with the ground attached to the frame somewhere. I guess I need to attach it to a body ground point instead of the frame.

 

[mrblaine]

I am late to the party but curious about this sentence “The way it is tucked in next to the mount on the 97, I'm not sure I would have always noticed it though.” - can you describe what you saw on your 1997? I have the same year but don’t recall any grounding wire or strap to the frame and starting to think that might contribute to my higher than desired SWR om my bumper / tire carrier combo mounted 2m radio antenna.

There is a ground wire to the engine block from the right side motor mount on the frame. The one here looks like a black 2 conductor boat cable in 16 gauge.

 

[Jerry Bransford]

Funny that this came up in my feed at the bottom today. I'm setting up my Jeep to be flat towed and my brake setup requires the negative from the RV to connect to the negative of the Jeep for both the Jeep tail lights but also for a built in battery charger on the brake system. The long 4 conductor wire was going to be routed back toward the back with the ground attached to the frame somewhere. I guess I need to attach it to a body ground point instead of the frame.

Ground it to the frame or tub, whichever is easiest for you. Either will be fine for a tail light circuit.

 

[Old_Crow]

I think I ran the ground wire from my lighting harness to the headlight ground screw on the left front inner fender. It was easy to get to.
I'll be pulling a Demco Stay-in-Play Duo braking system off of my TJ now that I'm towing on a trailer. Neat system with no extra hookups between the Jeep and the tow vehicle except the breakaway cable.

 

[Stinkbug]

Because "dots" on body mount bushings are apparently a piss poor electrical solution.
And wire costs money, obviously the factory install works "good enough " for most cases.
But I agree with the wired bonding approach if you need it.

I have little understanding of electricity and electronics. Are the terms grounded and bonded interchangeable? When I think of grounded, I think of a wire or cable. When I think of bonded I think of those woven straps commonly referenced in CB or ham radio threads.

 

[mrblaine]

I have little understanding electiciy and electronics. Are the terms grounded and bonded interchangeable? When I think of grounded, I think of a wire or cable. When I think of bonded I think of those woven straps commonly referenced in CB or ham radio threads.

Just replace grounded and bonded with connected electrically.

 

[jjvw]

I have little understanding electiciy and electronics. Are the terms grounded and bonded interchangeable? When I think of grounded, I think of a wire or cable. When I think of bonded I think of those woven straps commonly referenced in CB or ham radio threads.

Similar difference. Bonding is connecting stuff together and is ultimately connected to ground.

 

[Zorba]

I thought bonding involved women in leather!

 

[jjvw]

I thought bonding involved women in leather!

Aggressively wholesome!

 

[Apparition]

I thought bonding involved women in leather!

 

[SSTJ]

And I'm not referring to the early model ground strap that clips on the frame for killing static spark at the filler neck.

Or the little small gauge ground from the motor to the frame at the right side motor mount.

I'm talking about a real ground like you would use for actual electrical stuff of decent amp draw.

Just returned to this thread today. Now that it's 5 pages long, would you be up for summarizing the conclusion here on the original post?

 

[mrblaine]

Just returned to this thread today. Now that it's 5 pages long, would you be up for summarizing the conclusion here on the original post?

We don't know what we don't know. There is no consistent intentional connection between the tub and frame that one would actually consider an appropriate ground path. The battery is not intentionally grounded to the frame like it is to the engine block and tub.

There are accidental ground paths like the steering column, brake lines, and maybe some stuff we have overlooked or missed. The early connection between engine block and frame by the right side shock mount is more circuitous than a real intentional ground should be for reasonable current loads. In other words, if it was a real ground from the battery to the frame, it would do just that, a wire of reasonable size out of the negative battery harness that went to a ground point on the frame.

Oddly, the brake light on the dash is tripped when the switch plunger grounds the connection to the combo block, then through the brake lines, then to the master, then to the booster, then to the tub. Just bizarre.