Bad Ground side effects

Mark_BX25D

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Bx25D
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Actually that's false.
That's not false. What I said is exactly correct. We were discussing what could cause a bad VOLTAGE READING at the key switch.

You need to check a circuit under a load. Even a minuscule connection can show good battery voltage. But once load is applied, power can drop off due to bad connection.
True statement, but not what we were discussing.
 

BruceP

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G5200H
Aug 7, 2016
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when I turn the damned key to start it , sometimes there’s no lights on the dash , no sound of the cutoff solenoid working or the engine cranking. Other times when I turn the key the light light up on the dash and I get a couple of cranks on the e gine and then boom, it lol goes dead again.
Have you cleaned the guts of the keyswitch as I described in post #9 ?
 

Soonerdad

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G1800
Jun 12, 2022
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Update. Battery tested good at rest . Did have a intermittent bad ground. Fixed it and then jumped it off. Pulled dynamo leads off and tested at max RPM . ZERO output .ZERO. In fact after about a minute I could smell the belt . Danged dynamo was frozen up. No rotation at all. Frozen dead. . Think I found the issue .
 
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Soonerdad

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Been away from forums for a few years. Upon returning, CIVILITY has noticeably diminished.
Comment @ your own peril should be a posted warning .
Yes , I would agree. Civility is hard to come by with the anonymity of a keyboard. Folks say things behind a keyboard they would never likely say in person and that’s a shame.
 
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South 40

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Be sure to check the entire wiring harness for critters chewing on things, I have a Husky mower I am working on now, and they chewed up one of the plug wires and a hot wire feeding bot coils, really frustrating. Also take every ground connection completely loose clean the connector and sand the connection point, apply a tad bit of grease and bolt it back on.

Also replace all the fuses, I can't count the number of times I have had a blown fuse that breaks when hot and then reconnects when cooled down, worst issue to track down there is.

Cheers
Samantha
 
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Tx Jim

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Just an added thought, but remember the ground circuit starts at the negative battery terminal. Removing the clamp, cleaning, and making sure it goes back on tight is a good starting point.
I disagree battery ground circuit begins at tractor frame not negative battery terminal!! My electrical diagnostic experience has been frame connection of battery cable is overlooked more often than cleaned & tightened.
 
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GreensvilleJay

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To add to the 'ground' confusion ,I've had tractors and cars where the POSITIVE terminal was the 'ground'. The negative of a battery doesn't HAVE to be 'grounded'.
However, since alternators came out, most machines are now 'negative' ground,since most alternators produce a +ve voltage(cheaper back then), though you can buy =ve output alternators.
Then there is no 'ground' on a tractor, if you consider Mother Earth to be the official 'ground'. I've used her as the 'return path' for electrons for decades in my remote communications systems.
Over the past few decades, 'convention' has created 'negative ground' as being the 'norm',well, for most....
 
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Henro

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I disagree battery ground circuit begins at tractor frame not negative battery terminal!! My electrical diagnostic experience has been frame connection of battery cable is overlooked more often than cleaned & tightened.
That’s just semantics. Electrically the battery negative terminal, along with connections and wiring between the terminal and the tractor frame are all the same. Everything is part of the “common” side of the circuit. As GVJ says, there is technically no ground on a vehicle generally. Just a hot side and a common side to the circuit.

Agree the frame connection is often overlooked.
 

Tx Jim

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Semantics or no semantics the common side of battery connection has be called ""ground as long as I can remember"" & that's about 70 years
 

Tx Jim

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To add to the 'ground' confusion ,I've had tractors and cars where the POSITIVE terminal was the 'ground'. The negative of a battery doesn't HAVE to be 'grounded'.
However, since alternators came out, most machines are now 'negative' ground,since most alternators produce a +ve voltage(cheaper back then), though you can buy =ve output alternators.
I checked Kubota tractors back through the late 70's & Kubota tractors had positive battery cable to starter solenoid post & negative battery cable attached to tractor frame.
 

ejb11235

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I disagree battery ground circuit begins at tractor frame not negative battery terminal!! My electrical diagnostic experience has been frame connection of battery cable is overlooked more often than cleaned & tightened.
I'm confused about what distinction you're trying to make. @Henro was pointing out the importance of checking the battery negative to frame connection, which you apparently agree with. What is it about the statement that "ground circuit starts at the negative battery terminal" do you find incorrect? I guess technically once the engine is started and the alternator is producing voltage, you could remove the battery and then the ground would "start" at the frame. :unsure:
 

ejb11235

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Semantics or no semantics the common side of battery connection has be called ""ground as long as I can remember"" & that's about 70 years
I'm so confused ... you seem to be disagreeing with something that you agree with. I need more coffee.:coffee:

Are you talking about situations where the positive battery terminal is the common?
 
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ejb11235

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Press new bearings into the dynamo and it is good for another 10k hours. (I would expect two '2RS' bearings to cost less than $10)
I love this! Reminds me of my two success stories from years ago on my Volvo 145 station wagon. Young but not dumb. First was when I figured out that one of diodes in the alternator was bad, so I replaced it instead of buying a whole new alternator. Second was replacing upper and lower bushings in the distributor ... found some where the OD was perfect press fit and the ID was slightly small ... pressed them in with a drill press, then bought a properly sized ream and did a "line bore" using the same drill press to get the proper tolerance. Both the alternator and distributor worked for years. It was extremely satisfying.
 

Tx Jim

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I'm confused about what distinction you're trying to make. @Henro was pointing out the importance of checking the battery negative to frame connection, which you apparently agree with. What is it about the statement that "ground circuit starts at the negative battery terminal" do you find incorrect? I guess technically once the engine is started and the alternator is producing voltage, you could remove the battery and then the ground would "start" at the frame. :unsure:
I'm sorry I added to your confusion. I was attempting to state common connection didn't terminate at battery negative post as Henro stated but continued to frame.

If battery common IE ground cable is disconnected alternator will still have an electrical frame(common) connection. With newer type electrical systems I'll advise against operating alternator with ground IE common battery cable disconnected.

In my advancing age sometimes my reading comprehension causes me to interpret replies INCORRECTLY.
 
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ejb11235

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I'm sorry I added to your confusion. I was attempting to state common connection didn't terminate at battery negative post as Henro stated but continued to frame.

If battery common IE ground cable is disconnected alternator will still have an electrical frame(common) connection. With newer type electrical systems I'll advise against operating alternator with ground IE common battery cable disconnected.

In my advancing age sometimes my reading comprehension causes me to interpret replies INCORRECTLY.
All good now. I knew you were trying to say something but I read and re-read your posts and could not for the life of me figure out what it was. My comment about disconnecting the alternator was simply a thought experiment attempting to determine what you were saying.

I think both you and @Henro agree and were making the same point that the connection between the battery negative (typically) and the frame is really important and often overlooked.

I think that the point you are trying to make about "termination" is that (on a negative-ground system) low/ground/common (whatever term you want to use) on electrical components are usually connected to the frame, not directly to the battery terminal. @Henro almost certainly knows that but did not explicitly state it. Regardless, this means that a electrical component can have a great connection to the frame, but if the battery negative doesn't also have a good connection to the frame then you're going to have a problem.
 

Henro

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I think that the point you are trying to make about "termination" is that (on a negative-ground system) low/ground/common (whatever term you want to use) on electrical components are usually connected to the frame, not directly to the battery terminal. @Henro almost certainly knows that but did not explicitly state it.
Regardless, this means that a electrical component can have a great connection to the frame, but if the battery negative doesn't also have a good connection to the frame then you're going to have a problem.
Exactly.

I guess my point was for the purpose of analysis, the tractor frame is just another conductor in the circuit. That conductor joins another, which is a wire that connects the frame to the battery terminal. Could be either battery terminal, but today mostly is the negative battery terminal.

For troubleshooting, generally one looks at the battery as the starting point, not some other connection.
 
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BruceP

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For troubleshooting, generally one looks at the battery as the starting point, not some other connection.
Incase it is not crystal-clear.... the REASON the battery-minus post is considered the 'beginning' of all circuits on the machine is because this is where the electrons themselves originate. (current flows from minus-to-plus)

The description some folks giving for the engine-case (frame) as the 'origination' is due to what is known as a "mecca ground". In circuit-design, A "mecca ground" is considered the node where all the current terminates.

Properly designed automotive circuits will rarely rely on the engine-case (frame) as a current-carrying component. This is because the current from EACH AND ALL of the circuits will be additive.

Some older machines may use one-wire sensors on the engine. (oil-pressure, water-temp....etc) This is a rare example of using the engine-case to carry current.

It is VERY poor wiring-practice to 'just hook to the frame' when one needs a ground. Suddenly, current is flowing thru metal which is NOT intended to carry current. It is FARRR better to always use engine-case as the "mecca ground"...and have a VERY heavy wire from engine-case to battery-minus. Even better, all the wires connected to the engine-case should be underneath the SAME BOLT on the engine-case.

I have personally troubleshot and diagnosed strange electrical problems such as "charging current from alternator passing through BEARINGS because engine-case was not connected to battery-minus" The only place the current could flow from alternator-minus was thru rotating engine-bearings to get back to the battery-minus.
 
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GreensvilleJay

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Most (all ?) 'riding mowers' are well known for 'bad grounds'. Typically the battery negative cable is short(saves money) ,and a big selftap screw is used to 'secure' it to rear 'frame' section, that itself is 'selftap screwed' to the middle section of the frame which of course is selftap screwed to the front frame section where the engine is bolted to. Any (every) time the 'frame' twists and bends those screws 'open' up the electrical circuit a wee bit and what SHOULD be a great path for the electrons becomes worse over the months. Add a little rust, it's gets more worse. I've run a #4 from battery to starter mtg bolt on several 'hard to start' riders. click, vrrooom ! problem solved.
 
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