Club 80-90 Forums

itchyfeet wrote:

California Dreamin wrote: All automotive electrical consumers are fused for a reason.

Martin please can you educate me as to where the fuse is for the main 6mm2 red feed cable from the battery to the fuse box, I can't see it on the van or the diagrams?

It looks to me like there isn't one from the fuse box to the ignition switch and from the ignition switch to the coil or stater trigger circuit either?

Dave lfc has installed a new engine recently so my thinking was it could have been a short in the carb electrics, which are daisy chained off the coil.

I have always though this was an accident waiting to happen along with the lack of fuse to the thermostat circuit in the black box.

thanks
Paul

There is always one....'consumers' in the traditional sense and if it was fused then it needs fusing but you knew that...some people.

Nope genuinely misundersood what you said and i dont suppose i was the only one

didnt understand your explanation either

im always keen to learn how it all works and not afraid to ask stupid questions

Admittedly sometimes I generalize otherwise answers would be far longer, even more complicated and certainly even more difficult to understand.

I certainly don't have all the answers...yes I was a factory VAG trained Grade 1 technician for 6 years (went onto Mercedes after that) but I didn't make the things thats for sure.
Do I know everything about Volkswagens...probably about 10% of what I would like to know.

Usually I don't post unless I am fairly clear about what the problem is but often I feel oblidged to reply when I see advice that could be dangerous (like the earlier post from harris121163)
Yes I generalized saying 'all consumers are fused' and on the whole they are.

(Generalizing) circuits that are fixed with rigid short runs of heavy rated cable, like the main supply to the fuse box, are very robust and considered to be so reliable that they don't need fusing. However, consumers and associated wiring, taken off this main feed are much less reliable so need fusing. An example of this would be window lift motors and heated rear windscreens that have wiring that is flexing through rubber gaiters going across apetures in doors and tailgates.

As all motor technicians will tell you, this wiring is very susceptable to 'fatigue' failure after flexing many thousands of times as doors and hatchbacks are opened & closed.
It would also be very impractical to fuse some circuits, the starter for instance, with near on 200amps flowing on a cold day starting a diesel the fuse wouldn't be far off the size of the wire...Massive!
I surmise, the fitting or otherwise of a fuse must have been decided at the design stage and based on the likelyhood of it needing to be there.... this means all but a few circuits are fused. As for those circuits that are not fused but appear to be AS vulnerable....well ask yourself this, how many times have you seen those circuits dangerously burnt out AS A RESULT. I've seen a few.

Martin

Thanks for the explanation
I wondered if I was missing something, I even went out to the van and took the fuse box off and went looking for extra fuses

I can't help thinking some of the unfused circuits on a 25+ year old van would be better off with an added fuse as they are way past they design life, I may have a go myself.

so back to the OP burnt out wire could be a short circuit so worth checking