Brake lights blowing fuse - 300TDi

Superaquarama said:

Hi Guys,
Got a towing job tomorrow, checking the trailer lights I found that not only were the trailer brake lights not working, the Landie's weren't either !
Fuse blown, fitted new but blew as soon as the pedal was touched. Removed & unplugged rear lights, still a short somewhere. Brake light switch wires look ok, as do such other wires that are easily visible.
Any ideas where & what to check next, anyone ?
Thanks,
Anthony

Click to expand...

Dippypud said:

Trace wires from pedal to fuse box, look at the green wire to see if it is chafed /shorted...
Must be fuse box side of pedal switch if the fuse is blowing with ignition on pedal not pressed ...
The pedal switch is behind the pedal box under bonnet...

Click to expand...

jamesmartin said:

its blowing when pedals pressed ,if its since fitting a trailer id start at the lighting socket

Click to expand...

The Mad Hat Man said:

Removed & unplugged rear lights, still a short somewhere. - so likely to be vehicle wiring.

Click to expand...

Dippypud said:

Clean out your tow socket, it may be properly filled with mud//water and causing a short on the brake electrics...
Look at any place where a wire goes through the body, over a chassis component or near anything metal. No easy way I'm afraid...

If you get a headlight bulb,....and some wires with some terminals you can make up a simple tool where you replace the fuse with a consumer unit...( the lheadlight bulb) you need to rig up some contacts to fit in either side of the fuse holder here your blowing fuse fits

It will light up bright when you have a short straight to earth..
If you go about wiggling wires and keep an eye on the bulb, it will go dim if you are near the short...ie when you momentarily break the live contact to the earth....

Click to expand...

The Mad Hat Man said:

dont use a headlight bulb - too low a resistance - use a sidelight or indicator bulb. the lower the wattage the betterer.

Click to expand...