Is the factory TJ frame electrically grounded to the body?

mrblaine

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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.
 

Zorba

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Short answer: I don't know. Slightly longer answer: I couldn't find any reference to an "official" tie in, so I installed this:
37c.jpg

In addition to beefing up the battery negative connections to the block and firewall. Maybe un-necessary, but I don't know and it was cheap and easy. #2 wire with star washers used.
 
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mrblaine

mrblaine

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Short answer: I don't know. Slightly longer answer: I couldn't find any reference to an "official" tie in, so I installed this:
View attachment 292983
In addition to beefing up the battery negative connections to the block and firewall. Maybe un-necessary, but I don't know and it was cheap and easy. #2 wire with star washers used.
What needs to ground to the frame that makes that necessary or even desirable?
 

Zorba

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What needs to ground to the frame that makes that necessary or even desirable?
See the winch circuit breaker thread - in short, IN ADDITION TO the usual negative return wire from winch to battery, I also grounded the winch up front to get a lower ground impedance (assuming said ground connection doesn't fail).
 
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mrblaine

mrblaine

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See the winch circuit breaker thread - in short, IN ADDITION TO the usual negative return wire from winch to battery, I also grounded the winch up front to get a lower ground impedance (assuming said ground connection doesn't fail).
Nice but none of that has anything to do with my goober question.
 

Zorba

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Nice but none of that has anything to do with my goober question.
True enough - you're asking the same question I was - and in absence of an answer I just added the jumper.

Interestingly, I did a test running the grounded winch without the return wire before I installed the jumper around the motor mount. It wouldn't run - so apparently there isn't an "official" connection between the frame and the rest of the Jeep; or it had been removed/messed up on mine. Installing the jumper enabled the winch to run.
 

Lou

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True enough - you're asking the same question I was - and in absence of an answer I just added the jumper.

Interestingly, I did a test running the grounded winch without the return wire before I installed the jumper around the motor mount. It wouldn't run - so apparently there isn't an "official" connection between the frame and the rest of the Jeep; or it had been removed/messed up on mine. Installing the jumper enabled the winch to run.
It’s because the frame isn’t intentionally grounded on a TJ.
 
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ColoJeep

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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.
Isn't this answered by taking a look at the body / frame mounts and look for a ground strap/wire ? Or the FSM ?
If you are going to add a high ampere usage devise, just run an independent ground to the battery
and while your at it bond the engine to the frame and bond the frame to the body.

I for one am very curious about this question Blaine . Anyone that already knows about the filler static strap
has the necessary skills to determine the answer to your question.;)
 

tr21triton

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Ah yeah I totally forgot that the frame is bolted to the body with no fork of isolator between them. Wait….yep but it only has the rubber isolator between the frame and body. there is no isolator between the head or the bolt and body or between the nut and frame
yep but it only has the rubber isolator between the frame and body. there is no isolator between the head or the bolt and body or between the nut and frame
 
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mrblaine

mrblaine

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Isn't this answered by taking a look at the body / frame mounts and look for a ground strap/wire ? Or the FSM ?
If you are going to add a high ampere usage devise, just run an independent ground to the battery
and while your at it bond the engine to the frame and bond the frame to the body.

I for one am very curious about this question Blaine . Anyone that already knows about the filler static strap
has the necessary skills to determine the answer to your question.;)
The question is did the factory intentionally ground the frame to the tub? I've looked, I've studied, I know how it all works down to the tiniest detail and outside of the two instances I mentioned in my first post, there is no intentional factory connection between the frame and the negative terminal on the battery.
 
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mrblaine

mrblaine

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And finally, there it is. What I missed is the mushroom stem bottoms out on the inside of that metal cap. Now I also understand why the mushroom caps have little raised dots on them. That is so they bite through the paint to ground the body to the frame.

I kept getting stuck on the rubber part of the upper that sticks down through the hole in the frame. So, the frame is grounded to the body in 11 places.
 

Lou

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And finally, there it is. What I missed is the mushroom stem bottoms out on the inside of that metal cap. Now I also understand why the mushroom caps have little raised dots on them. That is so they bite through the paint to ground the body to the frame.

I kept getting stuck on the rubber part of the upper that sticks down through the hole in the frame. So, the frame is grounded to the body in 11 places.
is the inside of the lower body mount cap rubber or bare metal? I don’t know without taking one off.
 
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mrblaine

mrblaine

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is the inside of the lower body mount cap rubber or bare metal? I don’t know without taking one off.
All 11, the 6 larger on the sides and 5 smaller lower caps are bare metal on the inside where the stem that the bolt goes through bottoms out. I'll get some pics here in a bit.
 
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Lou

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All 11, the 6 larger on the sides and 5 smaller lower caps are bare metal on the inside where the stem that the bolt goes through bottoms out. I'll get some pics here in a bit.
Does that metal extend to touch the frame? I don’t think it does personally.