Simple but useful little retrofit.

Parts needed :

1) 12V DC Piezo buzzer from Radioshack 273-0059 (less than $5)
2) some means of connecting 2 wires

Step 1.

Remove the drivers side under panel

Step 2.

Find the Red/grey wire coming from the headlight switch. Tap into this wire and connect to one of the wires of the piezo buzzer

Step 3.

Find the White/pink wire coming from the ignition switch. Tap into this wire and connect to the other side of the piezo buzzer.

Step 4.

With the ignition off, turn the headlights on. If the buzzer does not go off, reverse the wiring and try again. It should now go off. If you have the ignition on however, the buzzer will not sound.

A quick demonstration......


First I turn the ignition on. Then the headlights (The buzzer does not sound). Once I turn the ignition off (with the headlights still on) the buzzer goes off. Then turning the lights off, which silences the buzzer.

 

Good work!

An alternative is to use the driver's door light circuit so the buzzer sounds if the door is opened with the lights on.

Cheers
DD