I prefer to drive with my headlights on in daylight - the estimated improvement in recognition is 15% by othger vehicles and 19% by pedestrians - but occasionally forget to turn the headlights off in my Bay. There are plenty of kits available at around the $20 mark, but I don't need the sophistication/complexity of delays, door open checking etc. All I need is a simple reminder that when the ignition is off and the headlights are on I need to turn them off.
I bought a "mini piezo buzzer" (part # AB3462) from Jaycar today for $3.95, and installed it just by finding a point in the wiring rats' nest which is hot when the lights are on and another which is only hot when the ignition is on.
The particular buzzer cited above is QUITE LOUD, but that doesn't worry me as it only plays when I leave the lights on by mistake; more sensitive souls might like something a little more subtle, but there will be several available at your local electronics store.
hth
modulus ·