Electrical issue and question

[mjw357]

Sometimes the strip connecting the side posts are weak and break or burn up... but you did say you used another battery to check.

The way the side post connectors are made, even if the bolts are tight, they still may not make good contact with the metal part inside the end of the cable. Lots of space for dirt and corrosion in there. I am betting there is an issue with the cable.

 

[Code54]

View attachment Mule 500 elec system.pdf

First: Thank you all for your ideas and help!

I am using top mount cables (just uses a phillips screw into a nut on the underside of the terminal. - ATV style battery)

The only connector I touched was the key switch (unplugged it) so I was thinking that must have been my problem but I checked it several times and can find no issues there.

What really scares me is when I went to jump it (when i thought the battery must be dead - bad idea by the way) the wires smoked for a brief second. Not sure what ones but may have been the cable or there is a second smaller wire that runs from the positive terminal (with the main red wire)into the loom but that has a fuse. I blew the fuse when I first went to jump it and replaced it with another fuse of the exact same size and did not have a problem again.
I been looking at the online wiring parts list and it is simple enough. I attached it for your reference.

Tomorrow I will clean all the contacts, wire connections and frame termination points. try to triple check the switch connection and pray it runs :thumbsup:

 

[Code54]

Here is the update - Had a few minutes today and looked at it a bit more.
Still not working....

Put new ends on both of the battery cables and even redid a few splices that looked old and well worn. Red from battery goes straight to the starter and the black runs right to the bottom of the motor and grounds everything. Cleaned those connections also.

The small wire that attaches to the positive goes straight into the harness and it appears runs to the key switch. A small black wire that is on the negative post heads to the frame as a ground and is pigtailed off and that goes into the harness also. I followed all the wires I could and could not find anything tore up or damaged.
I did trace some small wires to a relay (guessing for the start circuit) so I checked with NAPA and got a new relay (for $10 figure it was worth it just due to the age.).
The only thing left in the circuit is the rectifier - not sure if it is good or bad at this point.....

I put the battery on the trickle charger and will let it sit for the next day and get up to full charge. Cleaned everything I can clean so once the battery is charged I will give it another go.

I am really stumped on what happened to the machine......

 

[k0ua]

Do this,
step 1: go buy a good voltmeter. They don't cost that much.

Step 2: Re install the charged battery.
Step 3: Hook back up the positive cable and place red lead of voltmeter on the terminal connection of the battery. Black lead on the negative battery terminal Reading should be at least 12.6 volts if it has come off of the charger recently. Remember you don't have the black ground lead of the machine hooked up yet. You may need a helper or 4 hands to complete this next step.

Step 4: Momentarily touch the ground to the negative lead while still taking the voltage reading with the meter and watch what happens to the voltage. NOTHING should happen, it should not draw any current, and the voltage should still be 12.6 but I suspect you will see one heck of a voltage drop and a fairly large arc. If that is the case you will have to find out what is drawing current. Alternator diodes bad?

Please try these things and report back.. This is simple scientific method diagnostics.

 

[timswi]

Here is the update - Had a few minutes today and looked at it a bit more.
Still not working....

Put new ends on both of the battery cables and even redid a few splices that looked old and well worn. Red from battery goes straight to the starter and the black runs right to the bottom of the motor and grounds everything. Cleaned those connections also.

The small wire that attaches to the positive goes straight into the harness and it appears runs to the key switch. A small black wire that is on the negative post heads to the frame as a ground and is pigtailed off and that goes into the harness also. I followed all the wires I could and could not find anything tore up or damaged.
I did trace some small wires to a relay (guessing for the start circuit) so I checked with NAPA and got a new relay (for $10 figure it was worth it just due to the age.).
The only thing left in the circuit is the rectifier - not sure if it is good or bad at this point.....

I put the battery on the trickle charger and will let it sit for the next day and get up to full charge. Cleaned everything I can clean so once the battery is charged I will give it another go.

I am really stumped on what happened to the machine......

Did you continuity test the ground? Hate to be a broken record but ---

 

[Code54]

I have tested the ground and everything came back good. (well I think so at least - below will explain it more)

I have a good volt meter and just know enough about it to be dangerous.... Never had a seconds worth of training on it, pretty much been figuring it out as I go - Not the best but better than nothing I guess.
I am working all day tomorrow and doubt I will make it back in time to check it but will hit it Jan 1 for sure!
Thanks for the advise and please don't worry about over describing things as I am just learning and maybe doing something wrong and not even know it.

 

[timswi]

I have tested the ground and everything came back good. (well I think so at least - below will explain it more)

I have a good volt meter and just know enough about it to be dangerous.... Never had a seconds worth of training on it, pretty much been figuring it out as I go - Not the best but better than nothing I guess.
I am working all day tomorrow and doubt I will make it back in time to check it but will hit it Jan 1 for sure!
Thanks for the advise and please don't worry about over describing things as I am just learning and maybe doing something wrong and not even know it.

..

Dude, it's all good--Ain't no electronics guy myself..Just suggesting what I've seen..:drink:

 

[Xfaxman]

-----------------------

I have a good volt meter and just know enough about it to be dangerous.... Never had a seconds worth of training on it, pretty much been figuring it out as I go - Not the best but better than nothing I guess.
I am working all day tomorrow and doubt I will make it back in time to check it but will hit it Jan 1 for sure!
Thanks for the advise and please don't worry about over describing things as I am just learning and maybe doing something wrong and not even know it.

This might help: Multimeter Tutorial

 

[Code54]

Thanks Guys!

Most of my learning on this type of stuff comes from the net and sitting in the shop trying to figure it out so your help is greatly appreciated!

 

[k0ua]

This might help: Multimeter Tutorial

this ought to be a sticky!