lights on warning buzzer - anyone installed one?

[Cees Klumper]

Last weekend I spend a couple of hours trying to install a Hella "lights are still on Dummy" warning buzzer (don't ask). I followed the installation instructions, but no matter what I tried the best I could get it to do was to go off with the lights on + the driver door CLOSED! Open the door and the buzzer would turn off. And I got it to sound with the lights OFF and the door open. But not with the obviously wanted combination of lights on + door open.

Has anyone succesfully fitted one of these buzzers and how did you hook it up?

Cees Klumper in Amsterdam
'69 white 280 SL automatic

[mdsalemi]

Cees,

Perhaps the driver (we know it isn't you, hence the "don't ask") is better suited to a 107 chassis?  I think they had these things as standard at some point in their life, but maybe only on US spec.

There are some schematics floating around, I know a few people emailed them to me, perhaps one of these would help?



Michael Salemi
1969 280SL
Signal Red w/Black Leather
Restored

[Tom]

I believe Jim Villers has done this.  He brought me a GM lights on buzzer that I have not installed.  Maybe Jim can post a how to and where he got the part.

Best,

Tom

_____________________________________________

1971 280sl Tunis Beige Metallic (restored & enhanced)
1971 280sl Tobacco Brown (low mileage stock)
_____________________________________________

[Cees Klumper]

The Hella buzzer I got came with its own schematic, but even following (I think) the instructions, I cannot get it to work. The fact that I can get it to buzz with the lights on and the door closed, and it stops when I open the door, makes me think that somehow the door switch turns off when the buzzer needs for it to turn on. So I even thought of adding a door switch that has 3 positions. I just don't know enough about electrical work to be able to work this out, even though it seems simple.
I took the car for a spin last Friday at lunchtime with a colleague - he drove the way back and neither of us thought to check the lights which had to go on briefly to go through a tunnel. Back in the parking lot at work, the sun was out bright so we did not notice the lights were still on. Until it was time to go home at the end of the afternoon ... lucky enough the company I work at, a scientific research company, as part of its activities has an extensive car powertrain research and development, as well as crash testing, facility. So getting a jump start was no problem, fortunately.

I bet Hands (Bob Smith) from Australia knows how to rig up this buzzer!

Cees Klumper in Amsterdam
'69 white 280 SL automatic

[knirk]

I needed a quick solution after coming back to a dead car one evening. My connection gives me buzzing when the ignition is switched off and the lights are still on - door position has no influence. I strapped a buzzer around one of the cables just below the fuse panel. And after some detective work I got it to buzz when connected to terminals 5 and 7. I just put the leads under the fuse it self. For now the thin cables to the buzzer comes out under the fuse cover. Later on I will move the buzzer under the dash and connect it to the terminals from the inside.

Per G. Birkeland
69 280 sl aut 834
Norway

[Naj ✝︎]

Cees,
I would say you need an extra door switch. The one already there has power all the time and thats not what you want. A very simple one with one wire connection and body to ground will do. You don't need the expensive MB switch.
You can take power from any of the parking lights/dash lights to power the buzzer and the door switch would provide ground when you open the door.
naj

65 230SL
68 280SL

[Cees Klumper]

Thanks a bunch guys - I thought that's what the problem was Naj. I think I prefer the door opening trigger over the ignition switching off, because I may want to leave the left or right parking lights on (the two light switch left positions) when the car is parked along the street. I will try this extra switch-to-ground and report back.

Cees Klumper in Amsterdam
'69 white 280 SL automatic

[Naj ✝︎]

Cees,
What's the Hella part # for the buzzer?
naj

65 230SL
68 280SL

[Cees Klumper]

I will check next time I'm at the garage Naj (which should be tonite) - I got it at a 'generic' auto parts store and it gives off a nice buzz!

Cees Klumper in Amsterdam
'69 white 280 SL automatic

[hands_aus]

Hey Cees,
I have never installed one of these, but if I looked at the circuit I might be able to figure out how to install it.

A question?
Does your buzzer work if the lights are on HIGH BEAM as well as LOW BEAM?

The door switch should be a MAKE contact.

Why not pick up the switched side of the underdash light as Naj suggested? One side will be to negative battery.
This light is operated by both doors and then you won't have to replace both door switches.

Bob (Brisbane,Australia)
RHD,1967 early 250 SL, auto

[Naj ✝︎]

Bob,
By dash lights, I meant illumination lights for the instruments/clock/heater levers.
The underdash ( courtesy ) light is ground full time and the power comes from the door switch. I don't see how this will work the buzzer when parking/head lights are 'ON'.
naj

65 230SL
68 280SL

[Cees Klumper]

Bob - I did try to attach one lead of the buzzer to the interior light, and the other to one of the fuses for the lights (actually I tried #'s 7 and . There was a difference in which one of the interior light wires I used but, again, I got no further than getting it to sound when the door CLOSED, rather than when it OPENED.

The schematic that came with the buzzer only said to attach the one wire to the switch wire of the door contact, and the other to the switch wire of the interior lights. I don't really even know what a "switch wire" is but I have, I think, figured out now that Naj's suggestion will probably work, since (as you also say), the door switch needs to be a MAKE contact, and it probably isn't now.

Cees Klumper in Amsterdam
'69 white 280 SL automatic

[hands_aus]

Hey Naj and Cees,

Naj,
Cees said that he wants the buzzer to work with the "wanted combination of lights on + door open."

Cees,
If you have a 12V test light you can ground (-VE) one side and then test for which of the under dash light contacts supplies the switched 12V (+VE).

Just a silly question, does your under dash light come on when the door is opened?

Bob (Brisbane,Australia)
RHD,1967 early 250 SL, auto

[Cees Klumper]

Tonite or tomorrow morning I will once again attack the buzzer issue. After more thought (prompted by your posts) I figured it is really quite simple: one lead should get a + from one of the dash lights, and the other (the '-') should connect to earth through the door switch. The problem I am pretty sure with the current door switch may be that it is on all the time, and DISconnects (interrupts) when the door is opened, as Naj points out. This is why I can get the buzzer to sound when the lights are on and the door is CLOSED, and turn off when the door is opened. So ... I will add a new switch that grounds when the door opens, and connect the other lead to the interior light fuse.
Bob - to answer your question, yes: the interior light comes on when I open the door.

I have another problem with the electricals that I will post separately, maybe this can be resolved at the same time (hazard warning lights and brake fluid low warning light do not work).

Cees Klumper in Amsterdam
'69 white 280 SL automatic

[Cees Klumper]

Naj had asked about the Hella buzzer part no: 3SB 004 438-802 12V

Cees Klumper in Amsterdam
'69 white 280 SL automatic

[Ricardo]

Cees ....we had a thread about this back in Oct.  
search for "warning buzzer"
Ricardo

[hands_aus]

Hey Cees,

The 280 sl wiring diagram shows the LEFT (your driver) door switch as a change over type with 5 wires going to it.
The right door switch is a make type with 2 wires going to it.

You should be able to pick a -VE at the under dash light. The side of the light bulb wiring away from the switch. It must connect to -ve somewhere.

Bob (Brisbane,Australia)
RHD,1967 early 250 SL, auto