smoking wiring

[Mark from the Fort]

Hmmm.
I put the ol' girl back in the barn last night and about 5 minutes after turing the lights on--I had smoke curling out from under the dash.
I immediately shut the whole tractor down, and noticed the "lights" lead coming from the ignition switch.
I assume there is a short SOMEWHERE.
The first 12" of rubber was melted off the wires starting at the key switch. I did not notice any burning anywhere else. If there was a short somewhere else, would the burn take place there as well? Just struck me odd the amount of heat and no noticable bare wires.
Thanks for any input. Mark

 

[John (UK)]

A good time to fit a fuse and holder in the power lead I think. As you say it can be anywhere, if you have lights at the rear, check the wiring that runs to the back end, very often this gets kicked with your feet. If you have headlights, the usual place for problems is where the wiring passes the front axle and goes up onto the Hood, it often gets caught between the Hood and the Radiator. For the rear wiring, we always used to pass the wiring through a length of fuel pipe and passed that through the hole in the flange between the rear axle housing and the transmission housing on the top front right side, it doesn't get damaged this way. If you have it running lower down it can get caught on scrub as it passes over it.As the lead to the switch is carrying all the power it is normal for that to burn first but you will find something else somewhere if you look, it could be inside a lamp, like a wire has come adrift and is shorting out...John

 

[slinMI]

It is most likely that this was caused by a poor connection at the connection of this wire to the switch. A short would cause heat all the way from the switch to the point of the short. Poor connections get hot and the heat travels down the wire from the poor connection. That is why homes catch on fire and never trip a breaker or blow a fuse. Notice how hot your toaster gets and the fuse does not blow. Resistance, which what bad connections are, cause heat. Ohms Law.