1970 Deville - disable key-in-lock buzzer?

[grantatx]

Hi Everyone,

I just re-wired my aftermarket stereo to draw from the factory radio under-dash fuse, but every time I have the stereo on, key in the ignition and open the door, the buzzer comes on and I get horrendous feedback through the stereo speakers. I see two options:

1) Disable the buzzer (which on this car is part of the horn relay according to the manual)
2) Find a way to filter out the interference on the circuit

As I have no idea how to 2), has anyone successfully disabled the buzzer and if so how did you do it? Of course I'm open to suggestions for option 1) also!

Thanks in advance,

Grant

[bcroe]

The buzzer was kind of a clever double use of the horn relay, but
that design is an awful radio interference (EMI) generator.  I have
no use for a key buzzer, but converted it to be a LIGHTS ON WHEN
EXITING buzzer.  If you want to disable it, I suggest unscrewing the
door switch (pushing in on the center post to avoid twisting up the
wires) and disconnecting/taping the wire going to the buzzer circuit. 
The other wire is for operating the interior lights. 

The LIGHTS ON alarm was so popular here, I was asked to install the
same type switch on the passenger side door for exiting there. 
Bruce Roe

[grantatx]

The buzzer was kind of a clever double use of the horn relay, but
that design is an awful radio interference (EMI) generator.  I have
no use for a key buzzer, but converted it to be a LIGHTS ON WHEN
EXITING buzzer.  If you want to disable it, I suggest unscrewing the
door switch (pushing in on the center post to avoid twisting up the
wires) and disconnecting/taping the wire going to the buzzer circuit. 
The other wire is for operating the interior lights. 

The LIGHTS ON alarm was so popular here, I was asked to install the
same type switch on the passenger side door for exiting there. 
Bruce Roe

Thanks very much Bruce, that sounds like a good option. I'll give it a go this weekend.

Cheers,

Grant

[Glen]

After having to jump start the wife’s car for the third time, because she left the lights on, I decided to put in an alarm.  It consisted of a Sonolert (electronic buzzer) and a diode.  It was connected to the ignition ckt and the dash light ckt.  When both are off there is no current flow.  With both on still no current flow.  If the ignition is on and the lights off the diode blocks the current flow.  With the lights on and the ignition off the sonolert sounds.  It only happened once.  After that she always pushed the light switch in to be sure the lights were off before she turned the ignition off, day or night. 

[Scot Minesinger]

Glen,

Another option is to use the twilight sentinel option.  For all three of my 1970 Cadillacs, I added that option, it easy to do and even better because it turns the lights off for you.  My 2007 Crown Vic does not have this option, so I'm trained to turn them off anyway.  I should add this option to the CV.

One time I left my lights on manually in the 1970 Cadillac and exited the car.  There was a buzzing sound and after I turned them off, the buzzer stopped, so this must be there already as maybe an option did not know I had.

Anyway, the key buzzer never bothers me.  Rarely do I exit the car with key in the ignition. 

[bcroe]

Here are methods I use for converting 60s and 70s key buzzers to
LIGHTS ON monitors.

My 68 is very long gone, as is anything that didn't have front disk
brakes.  I am thinking when I disconnected the buzzer door switch on
this car, I did not actually convert that horn relay design to LIGHTS ON. 
But you could and here is what I would try. 

Get a small 12V Normally Open contact relay, connect one coil wire to
your parking lights feed.  Disconnect the 2 wires going to the key
switch at the base of the steering column, and connect the one from
the door switch to the other coil wire.  Now the relay should click on
when lights are on and the door is opened.  Connect a Normally Open
relay wire to the other column wire (that goes to the horn relay. 
Connect the other NO wire to ground.  Should work. 

To make it work on the passenger door, get another drivers door
switch with some of the connecting wires from the yard.  Replace the
passenger switch with this, connect the extra switch wire to the wire
from the same contact on the drivers door. 

My later cars had a small buzzer on the fuse block.  I cut its wire to
battery and reconnected it to the parking light feed wire.  I found the
2 wires to the key switch at the base of the column and shorted them
together.

My 79 Eldo had some kind of light control that I was mostly ignoring.  One
night it failed, turned on lights, and left me with a dead battery.  The car
was parked in a very narrow drive where another car couldn't be pulled up
beside to jump. 

I really hate things that break.  I pulled that module and set it on the shelf
(of other failures) next modules for power ant, trunk pulldown, cruise
control, etc.  All I need is a bullet proof light buzzer.  Bruce Roe