Cadillac Seville 1978 - Key Buzzer / Ground Courtesy Lights / Cigarette Lighter

[cactusami]

Hi all
I have a strange problem with my Cadillac Seville 1978. Really hope to get some help.
While I was replacing the glove box light, suddenly (exactly when I was removing the glove box light/switch) the buzzer started to sound (while the passenger door was open) and the ground courtesy lights switched off at the same time. Since than, the buzzer always sounds as soon as I open any door.... doesn't mater which door and no mater if there is the key in the ignition. So if I come to the car, open a door, the buzzer immediately starts. As soon as I put the Key in or/and close the door, the buzzer stops. Also the ground courtesy light (both sides) does not work, when a door is open.

And now the really strange thing: When I put in the (driver) cigarette lighter, the buzzer comes and the courtesy lights work!!! But the cigarette lighter doesn't get hot or warm. And this happens also while I'm driving. So the door must not be open and the courtesy lights and the buzzer work until i pull out the cigarette lighter.

Does somebody have any ideas what that could be?
Great thanks from Switzerland
Markus

[mgbeda]

Check all your fuses.  Say, for example, the fuse for the glove box light blew when you took the switch out.  "But," I hear you protest, "the glove box light works."  However it could be working because it's getting power from some other source which is actually coming backwards through another circuit, like the cigarette lighter or the key buzzer.  I once had a problem with my clock stopping when I opened a door, which turned out to be a fuse (I don't remember whether it was the clock or the interior lights fuse).



-mB

[bcroe]

Hi all
I have a strange problem with my Cadillac Seville 1978. Really hope to get some help.
While I was replacing the glove box light, suddenly (exactly when I was removing the glove box light/switch) the buzzer started to sound (while the passenger door was open) and the ground courtesy lights switched off at the same time. Since than, the buzzer always sounds as soon as I open any door.... doesn't mater which door and no mater if there is the key in the ignition. So if I come to the car, open a door, the buzzer immediately starts. As soon as I put the Key in or/and close the door, the buzzer stops. Also the ground courtesy light (both sides) does not work, when a door is open.

And now the really strange thing: When I put in the (driver) cigarette lighter, the buzzer comes and the courtesy lights work!!! But the cigarette lighter doesn't get hot or warm. And this happens also while I'm driving. So the door must not be open and the courtesy lights and the buzzer work until i pull out the cigarette lighter.    Markus   

Certainly check out all fuses.  Get a drawing of the circuits involved.  Then you will need to use
your meter/12V test light to track down the problem.  The key buzzer circuit is shown on pages
6/7 of 1978 SEVILLE BY CADILLAC ELECTRICAL TROUBLESHOOTING MANUAL, catalog no S-1556. 
This is a good book to have for 78/79 Seville, given the wiring complexity.  Likely a little searching
will turn up a copy. 

Mine shows very little in common between the key buzzer ckt and other stuff.  I'd check out the
door switch, which needs to be securely grounded, and not shorted between multiple poles.  A
bad ground will introduce some very strange paths between supposedly unrelated functions. 
good luck, Bruce Roe

[cactusami]

Hi
Thank you very much for your answers... 

Anyway... I will bring my Seville to the garage next Monday because there are some other things to do.
But when I have time I will check all fuses before.

I really hope it's only a fuse. Because I can't understand what I did wrong. The only problem I probably caused is a short circuit while I was removing the bulb socket.

The electric Troubleshooting Manual I bought few weeks a go already. So I will give it to my mechanic.

I will give a feedback soon I hope.

Many greets
Markus 

[76eldo]

Check to see if the manual lists a "body" fuse and a "courtesy" fuse. Check them first.

You definitely have a blown fuse and are back feeding current from a different source.

Brian

[cactusami]

Check to see if the manual lists a "body" fuse and a "courtesy" fuse. Check them first.

You definitely have a blown fuse and are back feeding current from a different source.

Brian

I hope it's only a fuse... :-)
But the body fuse is ok..thats for sure...because I replaced it with a new one.

[Eric DeVirgilis CLC# 8621]

To my recollection, the door open/engine temp warning lamp were on the same circuit and were protected by a breaker, as opposed to a fuse.

In any case, verify all fuses and breakers. Definitely sounds like a blown fuse/breaker somewhere since the problem coincided with bulb replacement.

Sounds very con"fusing" - sorry I could not resist. 

[bcroe]

If 2 circuits are not already cross connected, a blown fuse won't make them interact.  But a
failing (common) ground will, causing a cross connect.  Its good to check on everything just
worked on at the time of the failure (if known). 

Just about anything can happen in a car, with shorts to ground or other wires, open circuits,
and (heaven forbid) mis connected wires.  I wire a large bulb in parallel with a blown fuse,
and also a socket that can take a circuit breaker or another fuse.  The wired blown fuse
plugs into the position where they keep blowing.  With everything off, you may be able to
get the light to go off.  Plug in the circuit breaker and start operating things till the light
comes on (indicating breaker opened, probably warm).  Now the circuit can be worked on
without blowing fuse after fuse.  The light will tell when its drawing current; with the circuit
breaker in the light means excessive current. 

My other tool is a 12V light with long test leads, big clip on one end and smaller on the other. 
Usually one clip or the other will match the spot being accessed, the other end may not matter. 
Its much easier to note a light on/off, than trying to hold meter probes in place and look at
the meter at the same time.  Understand, a meter is for precision measurements, we are
looking for very gross stuff here. 

I just fought an entrance light circuit that was blowing fuses in my 79 Eldo.  Narrowed it
down to the pair going over the headliner to the dome light.  The feed showed a short
between wires, but not to ground.  BUT that was even with the dome light disconnected,
AND NEITHER feed showed any continuity to the dome light???  I found the feed first ran
back to a pair of very poorly constructed (plastic) lights on each side just above the shelf,
one had melted/shorted, and apparently also managed to burn off the rest of the run to
the dome. I wasn't about to tear the whole top of the interior out of the car to patch up
those failure prone lights, so I just cut the wires and reran the feed directly to the dome
light.  Just to compound the problem, the dome was held with a couple push on washers
that aren't really re usable (once you manage to work them off).  I managed to put a
6-32 thread on the studs and use nuts, AFTER the one stud came out and had to be
Loc Tite ed back in.  Another time, I might try to re engineer those fixtures for cool
running LEDs, and I won't be running the feed over the headliner.  Bruce Roe

[cactusami]

Update...

I got my car back from service.
It was definitely a burned fuse and the lamp/switch from the glovebox was also bad. So my garage replaced it. I probably also could have make this, but I really had no energy at the moment and wanted not to make more wrong. Also I did not have a new switch... :-)

So you were right! Thanks for your help.

Many greets....Markus