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Rear Light Fuse Blows

Posted: Thu Aug 23, 2007 7:32 pm
by Stockport Dave
On tour of continent recently the fuse feeding the back lights blew. Replaced it - all OK then some time later blown again. Put a 25A fuse in - checked the wiring in the lights at the back, all seem OK. Blew again (intermittent). I cannot believe (please God) that there is a short in the loom. Does anyone have any experience of a similar problem or knowledge of problem areas in the route from the fuse box to the rear lights?

Re touring continent - I LOVE my Tom Tom lady (Tomgella - if Nigel can do it so can I). I know sat nav is for wimps but ohh to be told which lane, when & where & how - its great - It takes away a lot of the stress of driving on the wrong side! Wish they would make one for LIFE, ie don't do that, yes to him, no to her, invest in that, don't touch that with a barge pole! yes your bum does look big in that etc etc

Posted: Fri Aug 24, 2007 1:42 am
by bigdaddycain
This is a long shot... You say you have checked the wiring to the rear lights dave?

Could the rear fog light inadvertantly be switched on?

It's just possible that a strand or two of wire could be touching the opposite ve over bumps?

I'm probably way off,but its worth a quick check...

Posted: Fri Aug 24, 2007 10:06 am
by smartmonkey
Check or change the bulbs for starters.

Posted: Sat Aug 25, 2007 11:08 pm
by Rog
As an ex- professional auto electrician, albeit on a couple of specific models , I have seen it all, and that's on cars that haven't even got to the dealers yet! Let alone ten years down the line after much abuse.

I had a towbar fitted when I bought my Bongo and removal of one of the seats had me removing the interior side panels. I was not amused to see that one of the trailer wires had been caught by one of the screws on something during their re-fit and had spun itself into a mangled mess. Luckily it had not shorted to anything, but if I had not found it, who knows when it would have failed, burnt out the loom, set light to my Bongo or whatever :cry:

So in a nutshell a blowing fuse could be just about anything, from a wire trapped on manufacture under a seat mount, or heater blower fan mount. Bits of welding spatter sticking out of spot welds is another good one! Any spot weld can have a lovely sharp earthed probe, just waiting to work it's way into your loom till it finds some volty stuff. Has anyone counted the spotwelds on a bongo!

Don't panic though as these are worst case scenarios, just to prove that you should not take any new car for granted. Yours used to be ok, so something has finaly shorted or festered or broken off because of vibration or somebody has been tinkering and caused a potential fault that has now susfaced.

If you have the circuit diagram, systematically disconnect things so you
can isolate the fault to a particular branch. (buy a big bag of fuses) If the wire you are dealing with is long and has wires branching out to everywhere and it's granny from crimps or soldered joints within the loom you will have to find these and cut them apart to isolate individual branches untill you find that single bit of wire that is letting those damn electrons get out too fast!

Life is hard, and then you die!

But hopefully not before you have cruised around in a polished Bongo of your choice, with or without lights

Rog
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