A courtesy light delay is a great feature for your car. It
enables you to see to insert the ignition key and find your seatbelt when it is
dark outside, without having to leave the door open.
However, many cars lack this feature, particularly older
models. When the car door is opened, the cabin lights do light up but as soon as
the door is closed, the lights go out. This happens just when you are about to
get settled into the seat. Of course you can fumble around and find the interior
switch but wouldn’t it be nice if the lights stayed on automatically for a short
And wouldn’t it be classy if the lights faded out at the end of
the timing period instead of a sudden switch off?
Another feature that would be useful is to have the courtesy
light(s) automatically switch off whenever the parking lights are switched on.
This would allow you to drive off if ready to go, before the courtesy lights had
The final feature of this new design is its ease of
installation. Past courtesy light delay circuits have presented real problems
for installation because of the various wiring combinations for courtesy lights
in modern cars.
In presenting this new design, we particularly wanted solve the
connection problems presented by the popular "Electronics Australia" design from
the April 1997 issue. This design needed to be built in one of four versions,
meaning that it was a game of chance if the car’s wiring configuration was not
known. By contrast, in our new design, the same circuit will work in all
- Adjustable delay period from 7-40s
- Lights fade out at end of time period
- Courtesy lights switch off if parking lights switched on
- No standby current drain from battery when lights are off
- Universal circuit works with any 12V car system
- Low parts count
- Easy to install