Jcb wiring fire

[Danphill90]

Hi my jcb 3cx 1997 started smoking in the cab. I pulled back the foam where the wiper motor is and the wires had melted. Thought I'd sussed it but then started from dashboard and then from the little alert dash In front of steering wheel. So quickly disconnected the battery. Whilst fighting fires I found the handbrake cable to be glowing red hot even though the cable doesn't work.
Anybody know what could of caused the whole electrics and handbrake cable to heat up and melt? It's also melted some pipe for the brake fluid or power steering fluid not too sure. Apart from the odd oil leak she's been fine no starting issues etc.
Any info would be much appreciated.
Dan.

 

[Regy53]

Hi my jcb 3cx 1997 started smoking in the cab. I pulled back the foam where the wiper motor is and the wires had melted. Thought I'd sussed it but then started from dashboard and then from the little alert dash In front of steering wheel. So quickly disconnected the battery. Whilst fighting fires I found the handbrake cable to be glowing red hot even though the cable doesn't work.
Anybody know what could of caused the whole electrics and handbrake cable to heat up and melt? It's also melted some pipe for the brake fluid or power steering fluid not too sure. Apart from the odd oil leak she's been fine no starting issues etc.
Any info would be much appreciated.
Dan.

Hi Welcome

Bad earth somewhere i think

 

[Shovelhands]

I think it’s more likely to be a dead short in the wiring loom somewhere, possibly chaffed through somewhere and is shorting to the chassis or bodywork. Or possibly a hydraulic hose, if a live wire and a hydraulic hose rub together it will eventually short out on the wire within the hose.

 

[Danphill90]

Oh OK brilliant thanks iam not great with electrics but will have a good root through and see if I can see the culprit. Thanks for replying.

 

[Mogman]

Sounds like it may have shorted through the hand brake cable that’s where I’d be looking first

 

[Diggerdavey]

My guess would be main earth lead broken. Using any other route to earth which were not designed to carry current

 

[Gecko]

Bad earth somewhere i think

Definitely a bad earth.

You must have a solid earth to both the engine and the chassis.
(or the current will find an alternative path - as described)
but this may only be half the problem.
As Shovelhands suggests, there is likely to be some other damage causing a short.

 

[V8Druid]

had a short on me black cab (10 years older at '87), but was fortunate enough to spot it, as it happened ....
loom from engine bay comes into cab under the front of the cab to chassis interface and had rubbed through at connection point ....
was very lucky to be sat in her as it started to smoke and whipped the battery off ....
I never leave any of my gear 'live' ... always isolate or disconnect battery poles

As Mog says, I'd be looking at main earths, if the handbrake cable is carrying that level of current, but can't see why it would be?? battery is under bonnet (on mine anyway) and VERY close to starter/alternator/main earth points ... unless everything was on in the cab it'd be drawing negligible current - unless there is a live cable shorting to earth (through the h/brake cable )

 

[Left hooker]

had a short on me black cab (10 years older at '87), but was fortunate enough to spot it, as it happened ....
loom from engine bay comes into cab under the front of the cab to chassis interface and had rubbed through at connection point ....
was very lucky to be sat in her as it started to smoke and whipped the battery off ....
I never leave any of my gear 'live' ... always isolate or disconnect battery poles

As Mog says, I'd be looking at main earths, if the handbrake cable is carrying that level of current, but can't see why it would be?? battery is under bonnet (on mine anyway) and VERY close to starter/alternator/main earth points ... unless everything was on in the cab it'd be drawing negligible current - unless there is a live cable shorting to earth (through the h/brake cable )

Battery to engine earth rubbish ? Seeing as engine and transmission are rubber mounted it's going through the chassis and along handbrake cable to box and engine ??

 

[Gecko]

Spurred on by this thread, I've just returned from buying some heavy welding cable to replace any of mine that don't look 100%

 

[topkit]

Evening chaps first time back on here for a while, a very interesting post, a few years back i had a series 3 Jensen Interceptor and driving home one afternoon started to get choaking fumes in the cockpit i pulled over straight away opened the bonnet to see flames so i whipped the battery cable off, ran to a house to get a blanket hammered on this door and i explained to the lady of the house that i needed a blanket or towel pretty pronto and she turned around a relayed it all to her husband by which time i was running back to the car and fortunately a friend was passing and stopped, they were in the antiques trade and by a stroke of luck had a furniture blanket in their boot which i used to smother the fire! Turned out to ben a bad engine earth the next best earth was the throttle cable, the plastic outer sheath had started to melt and caused the fumes which alerted me that something was wrong. I always check my earths nowadays and often put an extra one on.

 

[JD450A]

Battery to engine earth rubbish ? Seeing as engine and transmission are rubber mounted it's going through the chassis and along handbrake cable to box and engine ??

Front Hydraulic Driveshaft from Crank - Hydraulic Pump. I've seen voltage track through that before....

 

[Gecko]

I've seen voltage track through that before....

Groan .... that means the current has gone through both uni-joints, the spline and either the pump bearings or the gears themselves.
That would spoil your day.