The car went for it's MOT today and failed :cry: because the brake lights weren't working. The guy said the fuse kept blowing and that there must be a short circuit *somewhere*.

 

Can anyone tell me if I put a 25 amp fuse in there instead of a twenty will this stop it blowing or is this a bad thing to do even if it was only temporary?

 

He pointed to the front and then the back of the car and said there's a short somewhere there.... Is there a wiring map of the car somewhere, or can anyone tell me where I should start looking to sort this out. Is there any other weird cause I should be looking for? All the other electrics seem fine.

 

Any help with this would be very much appreciated.

LOL!! dont put a higher rating fuse in. the rating has been worked out to protect your wiring. besides, if theres a dead short, anything less than a nail will still blow!! :D

 

1st of all, check to see if any other consumers come off the same fuse, if not then disconnect the rear lamps to see if the fuse still blows. if it does then somewhere along the wiring loom is prob shorted to the vehicle frame. (tailgate wiring is a fave on most cars for the centre brake light)

 

HTH

Thank you. Does this mean removing trim here there and everywhere? Will the wiring run down both sides of the car, under the carpet, down drivers side? Sorry if this is major league clueless.

looking at the wiring diag:

 

wiring diag

 

the wire runs from the fuse, through a connector to the stop lamp switch. through another connector to the warning light sensor. then onto the 2 rear tail lamps. the centre stop lamp is wired in before the sensor

 

best thing is to work back. check the continuity of the wiring with an ohmeter (should be open circuit to ground). as there is a few connectors, if you can find these it should be possible to isolate the section that has a short

Thanks again for that help. Will this mean stripping out lots of interior trim? Not looking forward to that.

 

This might show me up further for the clueless bugger I am, but if it's a short, does that mean that somewhere the wiring will be cut or exposed, and will have to be touching another wire or the metal of the bodywork, so I should look for somewhere where the wiring is damaged?

Thanks again for that help. Will this mean stripping out lots of interior trim? Not looking forward to that

 

depends where the connectors are located.

 

BTW, does the fuse blow straight away or when you put your foot on the brake??

before you start stripping the interior...

see if all 4 brakelight lamps are dual filaments/dual contact type lamps...if one (or more) isn't, the strangest things can happen.