[s-cars] RE: Audi S6 No Start

Huw Powell audi at humanspeakers.com
Sat Dec 24 16:24:32 EST 2005

> <rant>
> Given the complexity of the electrical systems (and getting
> worse in the future, until we'll need to be network engineers),
> why Audi and/or Bentley don't strip out and isolate the various
> modules (e.g, this is the ABS circuit wiring, and that circuit
> only) is beyond me. Yes, it will take more pages, but it will
> save the $$$ mechanic time. Having to follow a single wire
> through the maze across pages is silly. I usually re-draw just
> what I need, so I know what I'm dealing with.
> </>

Wait a minute... that's how they *have* been organized since 
approximately the type 44 and type 89 (not sure if the earliest type 44 
manuals are...).  That is, each function gets its own "mini-schematic," 
with the only reference to other functions being if they are soehow 

It takes a lot more paper, and in some ways is clearer, *but* it makes 
it really hard to diagnose things like a blown fuse, since there is no 
indication of where else a fuse may provide power on any given part of 
the diagram.

Example: My recent dead instrument cluster gauges.  Turned out their 
fuse was blown, but not because of them (it was the wires going into the 
trunk lid shorting out).  I literally had to leaf through the entire 
40-50 pages or so of diagrams looking for other instances of that fuse, 
until I had id'd it as also powering a few other circuits, which I could 
then check.

In the old style diagrams, there would have been one "picture" of the 
fuse, and lines leading to all the things it provided power for.

Admittedly, this can make tracing some wires a pain, but at least any 
traces that went from page to page were id'd with letters (and I used to 
highlight them with color and annotate some things myself).  I did once 
see a lovely old VW (Rabbit?) manual where the diagram was a four page 
or so foldout - and in glorious full color!  Those days are gone with 
the ever-increasing number of functions and circuits, of course.  And 
the cost of color printing...

Huw Powell



More information about the quattro mailing list