Fuse No.12

[Andrew Pawlisz <apawlisz@tufts.edu>]

Hi,

I would like to share my recent experience with Fuse#12.  When I bought
the car used (88 5ksq), reverse lights were not working.  Quattro
archives revealed that the trunk lid wires at the hinge deteriorate due
to constant flexing.  Sure enough the wires were broken up.  I have
fixed the problem and immediately fuse #12 blew.  Thinking it was a bad
switch I have checked it, but it was O.K.  Going back to the archives I
have discovered that the wire that goes from the fuse box to the switch
rubs against the transmission causing a short circuit.  I did not like
that possibility as that wire is not very accessible.  Already
contemplating running a separate wire from the fuse box to the switch,
have read on the list not too long ago that shorts are realively easy to
find as they smoke like crazy.  Went back to the car, popped the hood,
slipped in a new #12 15A and sharpened by senses.  Sure enough, I see a
puff of blue smoke coming from the front of the car.  What the x, I say,
as I know that the reverse light wiring is at the back of the hood.  I
jump to the area and what do I see? I see a fried multisensor!  Of all
the things that I was suspecting a bad multisensor would be the last
thing! First of all, I would not think that a failed sensor would create
a short.  Second, I did not think that the sensor receives enough
voltage or current to fry itself.  Third, I suspect that the CIS-E would
send me a fault code to tell me that the sensor is.  Anyway, I have made
a temporary "repair" by snipping one of the sensor wires that was
causing the short circuit.  Funny thing is that the temperature gauge is
still working.
My question is which system is controlled by the wire that I snipped?  I
suspect the circuit to the oxygen sensor as the car had problems passing
the emission.  The HC is between 175 and 237 ppm!

Is there a good source for a multisensor and how much should it cost?

Thanks

Andrew

Boston, MA
88 5ksq
84 4ks