Help no gauges! 1987 Audi Coupe GT

[Huw Powell]

  > I pulled off every panel around the steering column and around the
driver
> side. No wires show evidence of shorting out. The radio is aftermarket but
> is still working fine. The fuse blowing is #12.

Fuse #12, according to my trusty fusebox diagram:

http://www.humanspeakers.com/cgi-bin/audi_img.pl?image=fusebox.gif

goes to:

an unused terminal
the reverse light switch
the flasher switch
the headlight switch internal light
cruise control power

I suspect maybe the cruise control, it is under the radio,
approximately.  Try unplugging it.

> Short of constantly putting
> in a new fuse to see if it blows again how would I find the short with no
> power running through?

As soon as you turn the key on, power goes to fuse #12.  Try this.
remove the fuse.  turn the key on.  find the "hot" side of the fuse.
ignore it.  Hook up a test light from the battery to the "cold" side of
the fuse.  Any current flowing should light the bulb, even if dimly.
Try not to leave it on too long, although at least the bulb acts to
limit the current that can be drawn.

Then start unplugging things on the list above (as quickly as you can to
minimize the time you are energizing the short)  whent he light goes
out, you have your culprit, with any luck.

OR, you could set a meter to measure resistance and turn on the beeper
that goes off when it reads zero.  hook it up from the cold side of the
fuse to ground.  If he short is bad enough, it will beep.  Unplug stuff
until it stops.  The last thing you unplugged was the demon.

> How does one go about checking the circuits with Bentley?

hahaha.

Spend a few years learning to read the darn things comfortably, then
memorize them all, then sketch out what you are looking at on a piece of
paper in a way that makes it make sense...

> I've looked at the wiring diagram and everything seems to connect
> somehow to the instrument panel. The wires under the fuse box are as thick
> as pea soup. Help! Do I have to start from the fuse wires themselves and
> work my way back? Is there no better way?

with any luck isolating the components on the fuse and examining them
will save your butt.  If this does not work, you have to start
backktracking up the wires towards their source, the fusebox.

At least all the circuits on fuse #12 are in two connectors, as shown on
that image I listed above... there is room to undo the fuse box and
raise it a few inches, cutting your hands in a few places, to unplug
those connectors if you need to.

Good luck!

>>It started with a clicking sound under the steering column ... next
>>thing I knew I had no signal lights and no gauges except for the
>>speedometer ... I disconnected the instrument cluster and tried
>>replacing the fuse (again it blew). The ground wires appear to be
>>fine at the back of the instrument cluster and the wiring harness at
>>the front ... Any suggestions where to start checking for the short?
>
>
> Aftermarket radio installation wiring gone kaput?

--
Huw Powell

http://www.humanspeakers.com/audi

http://www.humanthoughts.org/