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JD 410D dash switches & tach not working

mg2361

mg2361

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Joe's correct. Definitely get yourself a digital meter, way easier for the novice. Once you go digital you will never go back:D. I still have one of those analog meters somewhere in my garage in storage. Probably been sitting there for 35 years now.Analog Voltmeter.png
 
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Delmer

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A digital multimeter is $3 at harbor freight, nothing wrong with them except they don't tolerate water as well as a good one.

The other thread was a loose ground wire, as far as I could tell. Checking the voltage at the logic module, ignition switch, relay etc. will show you what's wrong. BUT, ONLY if you're reading the voltage that each component is seeing, by measuring it's hot and ground. They all need BOTH.
 
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MayaWilson

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What does your volt meter say in when you connect it to the alternator when the machine is running?Is it charging?
 
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Richard Hathaway

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kansas
OK I found my good meter, it shows 14.3 at the battery and the alt when the hoe is running see pic below
IMG_3469.jpg

I assume this is the diode behind the alt maybe someone can verify it by the pic below for me,(sorry about the watermark) it shows voltage one way and when I switch the leads from my meter around it then shows 0.0 then after a second or to goes to showing OL.
a>

IMG_3470(3).jpg



Also with my machine running I get 14.3 Volts at both of the leads with the red arrows in the pic below

IMG_3471.jpg


Delmer said:
Checking the voltage at the logic module, ignition switch, relay etc. will show you what's wrong. BUT, ONLY if you're reading the voltage that each component is seeing, by measuring it's hot and ground.
Click to expand...
So the logic module is the little flat box about the size of a flask behind the fuze/relay block in the consol, is that correct? so I guess that is my next move is to check that, can I ask you is there anything special I need to do to check it, I assume I will need to know what wires go to what component coming out of it, sorry for all the questions..
Was so much easier when it use to just be a timing light and a set of points lol......
 
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Richard Hathaway

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kansas
if anyone may have a diagram of the logic module's wiring and the proper voltages for those wires I could sure use it, thank you guys/gals for all the help so far, this backhoe it is a JD 410D serial num
T041DG819318
 
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joeblow

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Now we are cooking with gas !! I will send you some info.The manual I have is for a 310D but they should be the same.If worst comes to worst and you can't find the problem then get some duct tape and stick it over the yellow flashing light on the dash.As long as its charging you should have no worries.I have found so many electrical problem just by pulling harness's apart and plugging them back in.Follow the harness and check the pins and get some contact cleaner and clean each one as you go.Good Luck!
 

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Richard Hathaway

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kansas
Ok will do, this is driving me nuts, its like an itch I cant scratch, the worry with the duct tape is that alarm may be needed for something important later and not available to warn me, like fluid related and that could cost alot of $ to keep operating thru that I think

EDIT: Oh and I forgot to say thanks for the files and advise my friend!
 
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Richard Hathaway

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kansas
Also another question, this may answer its-self when I get that module out and have a look at it but is there a way to look up the part number for my logic module? I am sure its probly expensive but would like to look at just replacing it as well, thanks.

this backhoe it is a JD 410D serial num
T041DG819318
 
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Chisumtrail

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Just asking the relay for the alternator is 6 volt right, all other are 12 volt. Have you ever used scribd.com, it has a complete test book for a 410D for viewing. They may have a free trial, I have used the site it for years.
 
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joeblow

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Chisumtrail said:
Just asking the relay for the alternator is 6 volt right, all other are 12 volt. Have you ever used scribd.com, it has a complete test book for a 410D for viewing. They may have a free trial, I have used the site it for years.
Click to expand...
You are absolutely right chisumtrail.It is powered off of the r terminal of the alternator AC volts .It would explain why the tach is not working.I had a similar problem with a 690E;24 volt system-12volt alt relay.That little mother would be a special order from Deere.That is the first thing I would replace.Now that we have established the thing is charging!
 
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Chisumtrail

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Yea it should have 6 volt stamped on it. The M39 purple wire that plugs in back of the alternator splits and goes to the prong 86 on relay and and tach. The power out of plug should be about 7 volts AC and you should have same voltage at 86 on relay and tach.
 
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Richard Hathaway

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kansas
Update:
so I switched out the alternator back to the old one again and after I did I noticed I switched the G02 wire and the P13 wire by not paying attn enough or shear stupidity, but I did notice it and corrected it but my question is shouldn't that have blown the alt fuze and or the mfwd fuze since it was on? because it did not blow any fuze and I did start the tractor with them switched.
 
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joeblow

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Richard Hathaway said:
Update:
so I switched out the alternator back to the old one again and after I did I noticed I switched the G02 wire and the P13 wire by not paying attn enough or shear stupidity, but I did notice it and corrected it but my question is shouldn't that have blown the alt fuze and or the mfwd fuze since it was on? because it did not blow any fuze and I did start the tractor with them switched.
Click to expand...
 

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joeblow

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Since I retired I teach HD mechanics at a local college and I tell my students that there are no mistakes in my class,only learning experiences .
 
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Richard Hathaway

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Right on, I appreciate all the help, I know you cant beat a guy at what he does, love this forum its a great place for help. Last year or maybe 2 years ago I replaced the alt and got those same wires switched I know it blew the mfwd fuze instantly, I even made a post about it here, so let me ask you this, why did it not blow it this time? just wondering if that should tell me something about my current issues?
 
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