Headlight Chime

Phred

Phred

Senior Member
I am looking to wire in a “headlights left on” buzzer/chime for my Model A and having challenges coming up with a wiring diagram to do it, as there are two factors to be met in order to trigger the buzzer: 1) the car must not be running (ignition key off) and 2) the headlights must be switched on.
In my case, the ignition key supplies power to the ignition coil as opposed to the original Model A wiring of having the ignition key interrupt the ignition ground.
For some of you with more electron management experience than me, this may be a relatively simple circuit. I would appreciate any assistance. Thank you in advance.
Peace, Phred
 
If you get it working be sure to let us less than knowledgeable electronic guys know the diagram.
 
You need a normally closed relay. Use the tail light wire to one side of the closed contact and the other side to the buzzer. Ground the other side of buzzer. Connect the coil side of the relay with the key wire on the ignition coil and ground the other side of relay coil
 
How about a buzzer and diode wired in series, then connected to the generator output post and headlight wire. When the generator isn't putting out voltage (engine off) the headlight current would feed through the buzzer and diode then through the generator to ground. If the engine is running and the lights on you'd have 6 volts on both side of the buzzer, so it wouldn't buzz. When you are driving with the lights off the diode would block the current from going through the buzzer and lights to ground.

I'd go the easy route and just look at the switch to see the handle is down, and look at the lights to see if they are on.
 
Jeff/Illinois said:
I unplug the one on my modern cars they get annoying!!
Click to expand...

on most newer cars the multi function chime module works with other circuits so unplugging it is most likely creating other issues... the better bet is to puncture the tiny speaker in the module.....
 
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Tom Wesenberg said:
I'd go the easy route and just look at the switch to see the handle is down, and look at the lights to see if they are on.
Click to expand...

That's the best idea yet Tom!!! :eek::eek: Or you could look at the AMP gauge before getting out.

Or you could install a normally open push button switch in the door jam connected to the tail lights so you get a buzz when you open the door with headlight on. Use a switch similar to more modern (50-70) dome light switch.
 
For the visual learners...
Lights%20ON%20Reminder%20jpg.jpg
 
Why is a diode even needed ?

In a standard positive earth system...

lights off no - from lights , + from genny earth, no sound.

lights on, engine running, - from lights, - from genny charging, no sound.

lights on, engine not running, - from lights, + from genny earth, buzz.
 
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pooch said:
Why is a diode even needed ?
In a standard positive earth system...
lights off no - from lights , + from genny earth, no sound.
lights on, engine running, - from lights, - from genny charging, no sound.
lights on, engine not running, - from lights, + from genny earth, buzz.
Click to expand...

Without the diode the buzzer, a rather low-current device, will sound with the engine running and the lights off. The generator output will flow through the buzzer and then through the tail light filament as a ground path.

If the buzzer normally draws 25ma on 6V and the tail light 300ma on 6V you will see only ~8% voltage drop across the buzzer if the tail light is used as a ground path. 7.2V (running) x92% = 6.6V. The buzzer will be LOUD. You need the diode.
 
OK, thanks Mike, forgot about the bulb filament .

I know just enough about electricals to get myself into trouble.
 
Diagram

The attached seems to be a diagram of BruceKC post #3.

A little bench testing, to satisfy my curiosity, with a SPDT 12 volt relay shows that it ought to work.

Thanks to all for your help
 

Attachments

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If you are using a 6 volt alternator, where can you connect in order to have equal voltage on each side of a buzzer when the engine is running? My problem with leaving lights on is when driving in the daytime and using the lights on to be a little more visible. Mike K's schematic for a generator makes it clear, but is there a hook up for a 6 volt alternator?
 
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