Rewiring my B8200

[fatjay]

Fort he past few days i've been plagued with electrical woes. Turn the key to start, and the oil light , glow plugs, headlights wouldn't come on. Which means no starting. Turn the key to glow plugs, and nothing. Turn the key to start, and no starter.

I took the dash off and tried to trace down any grounds or shorts that might cause the problem. Two days of chasing wires. Eventually everything unplugged but the fuel gauge, snip that, and life comes back to the other 4 leads, but low voltage. I unplug the harness to what looks like a voltage regulator(silver heat sync), and my voltage jumps from 3.8v to 11v.

Anyway, most of the wires are in bad shape, many are broken, and I can only see this becoming further of an issue in the future. The plan is to replace everything under the dash, the harnesses and all wires seem good.

I want to get it, at minimum, to the point where i can start it and move it to my heated garage from the unheated, as my toes go about completely numb after about an hour out there. From what I can gather, all I need to do is activate the glow plugs, then bang on the starter, and it should fire up. My diesel experience is large trucks where you still have electronic components, but as far as I can tell the b8200 requires no electricity when running, injectors are mechanical?

Any advice would be appreciated, I've been pounding my head on this for days. It was intermittent to start, but seems more persistent now, I need my tractor to be ready when I am, so I have to do this one way or another.

Here's the rats nest:

Here's the schematics from a B7200, which I think are close enough to get me there:

 

[85Hokie]

Thats a mess ! Glad you have wiring diagram! Let me spin it around so everyone can look too. If you get it started, gonna be hard to steer without that wheel - ok- I'll stop.

If you get it cranked - I am almost positive everything is mechanical, so if you get it running, you just have to close the injection pump to shut off.

I think you nailed it - wires that are brittle and not carrying the load. Corroded wires inside the insulation would be almost impossible to find. Since you hav the back of the switch exposed - you ought to be able to "jump" the key if need be - and in essence, bypass the switch.

[/IMG]

 

[fatjay]

Thanks for the vote of confidence.

Any chance you can tell me what that second black box is towards the bottom? No switches or anything of the sort. Not exposed outside, just sits there and isn't exposed.

Also there's a second voltage regulator, I think, under the hood. These aren't on my diagram, nor are they on the parts diagram at the kubota website. I'm not sure the one under the dash's job, but if I'm doing a rewire, I want to clean it up, a lot.

Edit: I also don't understand hte point of 19 on the key switch. Is it a ground?

Also, another diagram I have from the B7200:

 

[bxray]

Looks like yoy will need to hotwire things.
Disconnect the fusable link to osolate the bad wiring.
Run a jumper from the battery to the glow plugs to heat things up.
Then jump the starter.
Make sure it is out of gear.
Is the fuel shutodd manual?

Then get spools of wire matching the guage from the auto part store and replace one at a time.
Ray

 

[kubotasam]

Post #19 on the switch is hot when you turn the key to the preheat glow plug position.

 

[fatjay]

I wasn't actually able to locate the fusable link in that mess. Looks like someone's been in there already fiddling around. I'm just not sure what this other black box is.

 

[fatjay]

Post #19 on the switch is hot when you turn the key to the preheat glow plug position.

So both 17 and 19 are hot, with no ground? Or ground feeds through the plugs?

Edit: nevermind, it hought that through, it makes sense now.

 

[North Idaho Wolfman]

I think the second box is the flasher unit.
There should be only one voltage regulator / rectifier, picture of the other one?
You can put power to the plugs wait 30 sec, then put power to the small lead on the starter and it will start and run.
Pull the stop rod on the right side under the dash to make it stop.
The reason for two feeds to the glow plugs, one feed is a preheat feed and it goes through the glow plug indicator, second feed goes to the glowplug while it's cranking.

 

[Russell King]

You may be able to buy a new wiring harness from the dealer unless you like doing it by hand.


Sent from my iPad using Tapatalk

 

[fatjay]

I've seen some of the dealer prices. The wiring harness is 7 different harnesses.

The other regulator is right behind hte alternator under the hood. At least that's what I think it is, it could just be a box wire goes through.

 

[D2Cat]

You might go here to get a schematic of the B8200.

Look for "owner's manual" and go to the last page, I think.

www.kubotabooks.com/AutoIndex/index.php?dir=Tractor Owners...

You might be surprised what you may find price wise for at least the biggest part of the wiring harness at Western Kentucky Tractor.

http://wkytpstore.com/


Here's another place to check for a wiring harness.

http://www.tractorpartsasap.com/Kubota-Tractor-Parts-s/6498.htm

I've purchased an entire harness from them at a very reasonable price. They included everything under the hood including fuse holder and fuses.

 

[bxray]

To find the fusable like or disconnect the system.
The cable starts from the battery and continues to the starter.
The fusable link will be in the wire comming off the starter to the rest of the system.

If you can not find the fusable link then dissconnect the smaller cable off the starter.
Disconnect the ground first and reconnect after disconnecting the power.

Ray

 

[fatjay]

Found the issue. The hot wire going from the battery to the key switch went through a wiring harness, which melted and shorted out with other stuff. Was realy confusing me, because hte wire at the key showed 12v, but when I tried to bump the starter iwth it, nothing happened, because it was shorting iwth something else.

 

[bxray]

Great find!
Is there an issue with the connector in the back of the photo?
It looks funny.
Ray

 

[SDMauler]

If your talking about the box that's attached to the regulator in the schematic, that is the symbol for a connector.

You will want to remove the wire that's connected to the common bus that is attached to the glow plugs before you try jumping the battery to it, to avoid backfeeding a switch that might be in the wrong position, or bad wiring that may ground or short out.

 

[made609]

I just had the same symptoms this summer; turned out being a bad starter. I figure it shorted out internally. Couldn't figure why it wouldn't crank with everything bypassed, took it off and it spun on the jumper box. Took a chance and ordered a new one, put it on, problem solved. Only took me three frustrating weekends, replaced hot and ground wires while at it.

 

[torch]

That photo is a classic example of what happens when current is forced through a corroded connector -- it heats up. I've seen that many times on old motorcycles. As bxray points out, it looks like the connector in the background is suffering the same fate..

 

[fatjay]

I think I'm going to take those harnesses out of the picture and properly crimp and shrink wrap them. They all look bad. The back harness you point out, that wire is the heavy wire from the alternator to charge the battery, so it wouldn't surprise me if that was problematic as well.

I guess that's what happens when you store your tractor outside under pine tree's for years on end. I saw where the previous owner kept it, no way I would keep a tractor like that.

 

[Steveola]

Thank you for the ladder diagram, I really don't get along with pictoral diagrams and wind up color coding them, then redrawing in ladder format so I can follow along. Every time I use a pictoral diagram I think "this person really hates me and wants me to take it to a dealer."

Steve
our "farm" is a livestock rescue and resort

>> Here's the schematics from a B7200, which I think are close enough to get me there: