Lucas prince of darkness strikes again

[muddysteve]

Got a slightly annoying problem on the 110 that no amount of head scratching seems to solve

Fuse 1 has blown and it seems like a dead short on the circuit, it feeds the horn, interior light and main beam flash as far as i can see. 1st thought was the stalk switch (horn/main beam flash) but having disconnected it the fuse still blows.
It also has taken out my stereo so i've discontected that, it still blows.
I've disconected the interior light and switch, you guessed it it still blows.

Ive looked at as much of the loom as i can and cant see any worn insualtion etc so starting to loose the plot now

any ideas??????????

[extreme90]

does it blow straight away or when something is turned on ?

[unknownmanxman]

Have you tried putting a bigger fuse in?  :P

[Porny]

Hrmm... dead short then!!

One way to find the find the problem... use a head lamp bulb  

A H7 bulb is ideal as it only has two pins, but a H4 bulb can be used too (just make sure you know which is the earth leg)...

Using twin core wire (or two lengths or wire) connect one end to the two pins on the bulb (i.e. earth pin and feed pin) and then put the other two ends of the wire into the fuse holder - i.e. replace the fuse with the bulb and wiring.

If there is a direct short the bulb will light... then just go along the wiring moving and flexing bits of it till the bulb goes out.  When the bulb goes out, you've found the section of the wiring which has the fault.

Just make the leads on the bulb long enough that you can always see it...
A horn can also be used , but gets annoying after a bit if the fault can't be found.


Ian

[muddysteve]

top tip that porny

found the loom crushed at the back of the chassis next to a shiney new dent in the fuel tank,

tidied it up abit and all is well for now, will fix it properly when the weathers better  

[MuddyMike]

Hrmm... dead short then!!

One way to find the find the problem... use a head lamp bulb  


Just make the leads on the bulb long enough that you can always see it...
A horn can also be used , but gets annoying after a bit if the fault can't be found.


Ian

I have a little 12volt buzzer on a short length of twin core with clips on the end, super tool for fault finding.

Mike

[Berliner Beer]

top tip that porny

found the loom crushed at the back of the chassis next to a shiney new dent in the fuel tank,

tidied it up abit and all is well for now, will fix it properly when the weathers better  

Same thing happened to me. My side light stayed on despite switching of the lights. The loom had been squashed and erroded down to bare wire. The live feed to the alarm was keeping the lights on. Resulted in a small smoldering mess of wire. The rac saved me and she's all better now!