I have a '96 300zx NA. Recently I have been having problems with the
horn going off when the headlights are on. The nissan dealer service
shop traced the problem to a faulty diode (near the glove compartment)
with some exposed wires. It seems any time the wires are hit by any
moisture, the horn goes haywire. The problem only happens when driving
in the wet. The service shop said the problem required around a week's
worth of work to dismantle the dash and fix the faulty diode. They
also recommended taking it in to a body shop to fix any leaks in the
body so that water does not spray into the diode compartment.
Before going ahead with this obviously expensive repair, I was
looking to see if anyone here has any suggestions on a cheaper
alternative. Has anyone else had this problem and if they did, were
they hit with a big repair bill? Thanks for any advice.

Would have to see wiring diagram to see any possible connection between
horn, headlights, and diode... The part about the moisture on the diode
is quite puzzling. Never saw a diode problem caused by moisture. Kind
of makes me suspicious about the whole diagnosis story.

Professor
www.telstar-electronics.com

normally a diode would be in the power distribution center underhood not
quite sure i buy the diode diagnosis either sounds more like a short
somewhere in the system i have 10 yr electrical manual for imported cars
would have to check circuits to see if there is any correlation to the 2
circuitsand see if any diode in circuit.
"Professor" <briangriffey (AT) sbcglobal (DOT) net> wrote

The tech also mentioned something about the security system being
connected to the whole issue. Supposedly, that diode controls the
security system, horn and headlights. The latest manifestation is that
if the car has been standing in rain, the high beam goes on and stays
on even when the car is turned off. This results in battery drainage
and the car having to be jump started. As soon as the weather dries
up, the problem is gone.
I get the feeling I am being fleeced by my dealer so I appreciate
your feedback so I can make a more informed decision. Thanks.

<djmcreynol... (AT) bellsouth (DOT) net> wrote:

OK, that makes more sense... about the function of the diode being part
of an alarm system. Seems to me that you might have some issues with
the alarm. Have you tried disconnecting the alarm system to see if the
problem disappears?

Professor
www.telstar-electronics.com


RC wrote:

At the time, I had asked the tech and he said that the problem would
not go away if the alarm was disconnected. He recommended replacing
the part. I can have the dealer disconnect the alarm and see if that
helps.

Professor wrote:

Nissan uses diodes in the body of the car to do things like have both doors
work the dome lamp, but only the drivers door triggers the 'key left in
ignition' sensor or the 'headlights on' reminder, etc... I ran into it
installing an alarm in a 93 SE-R. (diode was built into a connector in the
drivers kick panel)

Gary K

"RC" <tukan (AT) sprintmail (DOT) com> wrote