Burned wiring harness

Ronnie Mathis

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How’s can I fix with out replacing it and what other damage do I need to be looking for
 

Rivets

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You need to start over with more info, as we are confused as to what you want. Please give us the following information. Model and serial numbers for your unit and engine. Nature of the problem or problems . What you have attempted to date. What specifically are you wanting to know. Anything else that you think might help us help you. With this info we can start the solutions, but without you’ll get no where.
 

StarTech

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Well you could do a hatch job on it as it will require at least wires of the matching colors, open barrel crimpers, picks for removal of terminal from housings, new housings if they are melted, Lots electrical tape to re-bundle the harness. For a layman this can be more the harness itself in costs. Especially when you got to buy the tools for an one time project, figuring which housings to buy and where to get them, multiple shipping costs.

Basically it is not just a simple thing to do for a layman. Personally I have been putting together a list of all the connectors and terminals that I have used here. I had to purchase two $70+ crimpers and several terminal removal tools, 20+ different 100 ft rolls of 18ga and 16ga along some 14ga and 12 ga spools plus 50 ft each of 6 ga red and black battery cable, various terminals including cable lugs, A hydraulic terminal crimper. And doesn't includes the heat shrink and other random terminals.

My customers never sees these costs and don't care; they just bitch about the costs of the parts installed and the labor charged.

On top this we don't even know why your harness burned in the first place. You could replace the harness and still have it to burn up again if there is shorted electrical items. This is really a job for a trained tech to do.
 

Ronnie Mathis

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I was told it needed a voltage regulator it is actually melted just don’t know where to start trying to illuminate carrying it to someone
 

sgkent

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good choice. As a mechanic I was assigned repairing damaged wiring harnesses on a few cars. It is a miserable experience if much is involved - and it assumes you find the cause before burning it up a second time. Kind of like replacing damaged transistors and diodes in a circuit. They cascade and if one does not get all the damaged ones, they do it again.
 

bertsmobile1

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You start with posting all you can find about your mower
Mower brand model number & serial number as found on the ID tag
And the same for the engine
Then you get your hands on the wiring diagram for your mower
After that you peel back the insulation at every plug & terminal and take a photograph, actually several photographs so you know which wire went into what position in what plug
Now you start cutting off the insulation but as you do you use twist ties or reuseable zip ties to keep the wires together and very importantly each side of where a wire exits the main loom, and all the time photo , photo , photo & even more photos
You will also need to remove the blower housing & flywheel to visually examine the stator

Then you look at the damaged wires, where the damage stated, where it ended & what wires are damaged
These will point towards what failed & where it failed
If you are lucky it will be just a couple of wires
The engine can be started with a jumper independent of the mower to check the regulator / rectifier if necessary.
When you know which wiring diagram is correct for your mower, print it out as big as possible. even if you have to go to an instant print shop and pay for a couple of prints.
I print most out in A2 size ≈ 24" x 32" and if they are not in colour I use coloured pencils or textas to over colour them so everything is easy to see
During normal running there are only 4 mower wires that have power flowing through them
1) power feed to mower from battery
2) power feed from alternator back to the battery
3) power feed to electric clutch
4) power feed to carb solenoid

All the other wires are ground wires and as such if they short to ground nothing happens to the loom ( mower might not run though )
And usually it will be numbers 1 or 2 as the PTO generally has a 5A or 7A fuse on it which will blow way before any wire gets hot enough to melt the insulation

So there is a start
As you have been warned, it will be a long & tedious task at best
If you are not bald now you will be when you have finished
We are here to help you if you want to tackle it yourself but it will usually be several weekends worth of work & your grass will not oblige by mowing itself .

The only times I have replaced a complete loom was because one customer wanted the mower fixed RIGHT NOW & did not care about the cost which was just under $ 1000 ( Aus ) and for the commercial customers where the mowers had done big hours & nearly every wire had hardened & broken off at the crimp terminals
 

StarTech

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During normal running there are only 4 mower wires that have power flowing through them
1) power feed to mower from battery
2) power feed from alternator back to the battery
3) power feed to electric clutch
4) power feed to carb solenoid

All the other wires are ground wires and as such if they short to ground nothing happens to the loom ( mower might not run though )
And usually it will be numbers 1 or 2 as the PTO generally has a 5A or 7A fuse on it which will blow way before any wire gets hot enough to melt the insulation
Not always; the 2002 Scag Turf Tiger I maintain for a customer has 12v running through the safeties so you can't assume all other wires besides the four listed are ground. Several OEM mowers here also has 12v running though the safeties.

Here is yet another case where the OP hasn't posted the equipment model numbers sop there is only guesses on how it is wired.

What worst is most OEMs are now not providing proper schematics. Several don't even provide a diagram of any kind so they can sell complete harnesses. Some just a very basic drawings. Some provide diagram only in service manuals that you must purchase, and few openly provide the diagrams.
 

sgkent

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he wrote: "carrying it to someone" maybe he can get a loaner. Hopefully the "someone" is detail oriented and good with wiring and circuits.
 

Ronnie Mathis

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Not always; the 2002 Scag Turf Tiger I maintain for a customer has 12v running through the safeties so you can't assume all other wires besides the four listed are ground. Several OEM mowers here also has 12v running though the safeties.

Here is yet another case where the OP hasn't posted the equipment model numbers sop there is only guesses on how it is wired.

What worst is most OEMs are now not providing proper schematics. Several don't even provide a diagram of any kind so they can sell complete harnesses. Some just a very basic drawings. Some provide diagram only in service manuals that you must purchase, and few openly provide the diagrams.
You start with posting all you can find about your mower
Mower brand model number & serial number as found on the ID tag
And the same for the engine
Then you get your hands on the wiring diagram for your mower
After that you peel back the insulation at every plug & terminal and take a photograph, actually several photographs so you know which wire went into what position in what plug
Now you start cutting off the insulation but as you do you use twist ties or reuseable zip ties to keep the wires together and very importantly each side of where a wire exits the main loom, and all the time photo , photo , photo & even more photos
You will also need to remove the blower housing & flywheel to visually examine the stator

Then you look at the damaged wires, where the damage stated, where it ended & what wires are damaged
These will point towards what failed & where it failed
If you are lucky it will be just a couple of wires
The engine can be started with a jumper independent of the mower to check the regulator / rectifier if necessary.
When you know which wiring diagram is correct for your mower, print it out as big as possible. even if you have to go to an instant print shop and pay for a couple of prints.
I print most out in A2 size ≈ 24" x 32" and if they are not in colour I use coloured pencils or textas to over colour them so everything is easy to see
During normal running there are only 4 mower wires that have power flowing through them
1) power feed to mower from battery
2) power feed from alternator back to the battery
3) power feed to electric clutch
4) power feed to carb solenoid

All the other wires are ground wires and as such if they short to ground nothing happens to the loom ( mower might not run though )
And usually it will be numbers 1 or 2 as the PTO generally has a 5A or 7A fuse on it which will blow way before any wire gets hot enough to melt the insulation

So there is a start
As you have been warned, it will be a long & tedious task at best
If you are not bald now you will be when you have finished
We are here to help you if you want to tackle it yourself but it will usually be several weekends worth of work & your grass will not oblige by mowing itself .

The only times I have replaced a complete loom was because one customer wanted the mower fixed RIGHT NOW & did not care about the cost which was just under $ 1000 ( Aus ) and for the commercial customers where the mowers had done big hours & nearly every wire had hardened & broken off at the crimp terminals
How much is a mower worth that is needing a complete wiring harness that’s 20-year-old Tiger cub
 

Rivets

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Mar 11, 2012
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14,683
All depends on who’s buying it And overall condition. To me a winter project might be worth $250. I know that seems low, but we’re taking a unit with a minimum of unknown electrical damage. You must remember you are selling a non running piece of equipment.
 
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