So after the embarrassment of leaving my lights on a couple of weeks ago, I started looking at headlight reminders. We take them for granted on newer cars but try finding a simple solution for older cars that is quick, easy and effective without buying a commercially available item or paying an auto sparkie to do it. I thought about designing something but came up with this instead.

I came up with a very quick idea that anyone can do with little or no experience in auto electrics. All for under $5 total.

You simply pick up a 12v buzzer which can be bought from Jaycar or any electronics store. It will need longer wires fitted to it. A couple of piggyback crimps completes the list. These allow you to leave the original wires untouched.


You need to connect the positive wire to the fuse that controls the headlights. This is only powered when the headlights are on.

The negative terminal goes to the switch that turns the light on when you open the door. This switch earths when the door opens. Hence the simplicity.

Very easy. If the lights are on and you open the door, the buzzer goes. It will not sound if the lights are off.

More than happy to offer assistance or advice if you wish to fit one yourself.

Handy mod, but being just on the door seems like it could become annoying. It would be good to hook it up so that when the lights are on and the door is opened when the ignition is off it sounds. Is that possible?

You can get a headlight warning from Narva, its $15 from Autobahn that does that.

I've fitted a couple of them, they work well and are very simple to install, one feed from the parker circuit, one from the door switch and an ignition wire so it only works when the ignition is turned off.

Surely you need to sense from the headlight circuit. The parkers are designed to be left on at times. Easily changed, but a simple mod that's required IMO if you need one of these.

You can get commercially available units but the ones I looked at were anywhere from $20 up to $50. If you are not up and up with auto electrics (I am but many are not) then attaching to ignition and the like can be dangerous territory. I would rarely leave the lights on and open the door anyway, so unlikely to bother me but if you do get out frequently at night then agreed, it could be annoying. The last one of these I built years ago was very much overthought - 2 relays, a buzzer and a lot of connections, this was a quick and simple yet effective way to get the same result.

If you wanted to run it so it only worked when the ignition was off, you could use a NC relay which would complete the circuit when the ignition was off but would be "open circuit" with the ignition on, hence it would not sound. I have plenty of relays sitting round (most have a NO and an NC pin) but felt in this case simple was the key. It only took 10 minutes from start to finish to do.

71 and later VWs turn the headlights off when you turn the car off and just leave the parkers on.

THrough the day it can be very easy to not notice the parkers left on.

The 71 and later ignition switches also have a terminal for the side marker system which is only live when the ignition is off and open circuit when its on, it's handy for powering things like headlight reminders and I used it for my key in/door ajar warning as the factory ones work even when the ignition is on for some stupid reason.

That's a ripper little mod Pfillery. Simple, piss-easy to fit, no mess!