Anyone know how to read Bentley wiring diagrams

[Huw Powell]

> I have a question about my 86 5ktq.  My turn signals and windshield
> wipers don't work.  I have the Bentley Electrical Manual and the
> drawing for this system (page 97.338) doesn't make sense.  The problem
> is I have 12V at point 30a but then how does it make it to point 49a?
> Does power go through the emergency flasher relay or what?  I see no
> other way that the turn signals would work but when I tested this
> theory in the car the only way the flasher relay gets power is if the
> hazard switch is ON.  I have taken the whole switch assembly apart and
> cleaned the contacts but the problem remains.
> 
> My main question is where does the turn signals get their power from
> and is there another fuse/relay somewhere I don't know about?

I'll try to take a stab at this, I will follow the current path from
"source" (12v) to "sink" (ground) and explain how it works as I go
along.

First, there are two separate power sources for the flashing light
system.  Battery power makes its way via fuse 2, and ignition power via
fuse 12.  These go to pins 30 and 15 respectively on the emerg. flasher
switch.

In its rest position, this switch allows the ignition power to go to the
flasher unit and then to the turn signal switch *and* back to the
"other" part of the flasher switch.  When activated, the emerg. switch
swaps in the battery power to the flasher unit, and also connects the
left and right signal light wires together to that "other" wire from the
flasher.  At this point the juice goes battery to 30/49 in emerg sw. to
49 in flasher to 49a at emerg switch to all four signal lights to
ground.  since current then flows, the flasher operates and the lights
all turn on and off til your battery dies.

The rest position, ie emerg. off, the "15" ignition juice goes to the
flasher unit and then to the signal switch at 49a, where it can be sent
to either the left or right set of bulbs and then to ground, completing
the circuit and making your intentions apparent to those around you.

I have left out wire colors, if you can follow my description while
looking at your manual you will see them for yourself.

Hope this helps!

-- 
Huw Powell

http://www.humanspeakers.com/audi/

http://www.humanthoughts.org/