auto off dome light?

[james]

More than once the dome light in my WRX was accidentally left on and almost
killed my battery.

Is there a way to modify it so that the dome light turns off after, say, 15
minutes? Or replace the bulb with a LED-based light?

 

[Bugalugs]

More than once the dome light in my WRX was accidentally left on and
almost killed my battery.

Is there a way to modify it so that the dome light turns off after, say,
15 minutes? Or replace the bulb with a LED-based light?

There are LED festoon bulbs for dome light replacement.

I looked at them some months ago but procrastinated and didn't proceed
because I wasn't sure about the auto-dimming when the door closed. The
question I never got around to answering was, did the present
incandescent bulb dim because of reducing voltage or reducing current,
and would the LED work the same or be destroyed.

I know just enough about electricity to be dangerous.

 

[Uncle Ben]

There are LED festoon bulbs for dome light replacement.

I looked at them some months ago but procrastinated and didn't proceed
because I wasn't sure about the auto-dimming when the door closed. The
question I never got around to answering was, did the present
incandescent bulb dim because of reducing voltage or reducing current,
and would the LED work the same or be destroyed.

I know just enough about electricity to be dangerous.

If the bulb dims, it means that the voltage across it is reduced,
causing the current through it to be reduced If the LED bulb works at
full voltage, it will not be damaged when the voltage falls.

(I have no specific knowledge about these bulbs aside from owning a
few flashlights using them. But the general principle is valid.)

Uncle Ben

 

[Hachiroku $B%O%A%m%/(B]

There are LED festoon bulbs for dome light replacement.

I looked at them some months ago but procrastinated and didn't proceed
because I wasn't sure about the auto-dimming when the door closed. The
question I never got around to answering was, did the present
incandescent bulb dim because of reducing voltage or reducing current,
and would the LED work the same or be destroyed.

I know just enough about electricity to be dangerous.

It's fun, isn't it?

Except having a recurring twitch from being zapped too many t-t-times...

 

[Hachiroku $B%O%A%m%/(B]

More than once the dome light in my WRX was accidentally left on and almost
killed my battery.

Is there a way to modify it so that the dome light turns off after, say, 15
minutes? Or replace the bulb with a LED-based light?

The LED based bulb still uses 12V. There is a voltage-drop resistor in
there that drops the voltage to 3 or 5V depending on the LED, but to the
overall circuit it still looks like 12V. It ain't helping on current,
either, because the resistor may actually be drawing more current than the
OEM bulb is.

 

[Tony Hwang]

The LED based bulb still uses 12V. There is a voltage-drop resistor in
there that drops the voltage to 3 or 5V depending on the LED, but to the
overall circuit it still looks like 12V. It ain't helping on current,
either, because the resistor may actually be drawing more current than the
OEM bulb is.

Hi,
May I be differ? LED current consumption is way less than a bulb. In the
range of miliiamps. Resistors main job is to drop the voltage at that
current draw. Overall LED will use way less energy(literally no heat).
Refresh your high school physics; Ohm's law. Look at the size of
resistor which is typically less than 1/2 Watt size which means?..... I
replaced all the illumnation on my patio in the back yard with LEDs.
They consume 1W each vs. bulbs which is ~7W and up.

 

[VanguardLH]

More than once the dome light in my WRX was accidentally left on and almost
killed my battery.

Is there a way to modify it so that the dome light turns off after, say, 15
minutes? Or replace the bulb with a LED-based light?

http://www.globalspec.com/FeaturedProducts/Detail/Serial_12VLED_Driver_for_up_to_three_LEDs/29400/0

The 12V LED bulb (which is an assembly with an internal regulator) would
draw less current. That can affect any flasher devices that rely on the
current draw, like the old flasher units with bimetallic strips that
rely on heat to flex the strip so the current draw determines the rate
at which they heat up and if they heat enough to flex to make connect
(whereupon they cool and flex to break the contact). Timer circuits
don't care about the load. Even with a blown bulb (i.e., no load), the
circuit is still timed.

http://www.superbrightleds.com/1157.htm
http://www.superbrightleds.com/carbulb-notes.htm

http://www.sylvania.com/ConsumerProducts/AutomotiveLighting/LampReplacementGuide/

You didn't specify the year for your WRX so you'll have to search
yourself. Once you used the Sylvania site to identify your bulb, you
can then find out what LED replacement to use. For example, if it is a
DE3175, go to the superbrightleds site and look in the cross-reference
list to see that you need their 3022 model, a festoon style bulb. You
can even pick a color. They have some high-power models but even those
probably won't put out as much light as an incandescent bulb. I didn't
see them list how much current they draw (plus you would have to find
out how much the incandescent model draws to do a comparison).

http://www.next.gr/automotive/lighting/

I suspect you don't want to actually build the thing (etch a PCB, solder
the components together, put into a box, splice into the dome light
wire, run a wire to a constant 12v source). You might know someone that
can fab this for you.

http://www.polytron-corp.com/products_automotive.html

This has the advantage of not only turning off the dome light when you
leave but leaving the dome light on as you enter (so you can see where
to push in the key for the ignition switch, for example). However, 5
minutes would be way too long to leave on the dome light when you
entered the vehicle (or anytime you opened the door). With some more
Googling (which the OP should do), I'm sure other units are available
that can perform a similar function but be more appropriate for dome
light timing that for cargo light timing. I'll let you do the Google
searching.

You sure there isn't a timer for the dome light? From some articles,
like:

http://74.125.113.132/search?q=cach...e+light"++timer++wrx&cd=5&hl=en&ct=clnk&gl=us
http://74.125.113.132/search?q=cach...e+light"++timer++wrx&cd=9&hl=en&ct=clnk&gl=us

A timed dome light feature is mentioned. Maybe you have the switch on
the dome light in the wrong position. Maybe it's not included unless
you get some trim package, but that would mean the part is available
(but probably rather pricey from the dealer's parts store). There
appears a "On w/Open Doors" setting as mentioned at
http://legacygt.com/forums/archive/index.php/t-79918.html. Could be the
timer went bad (so you might get it replaced under warranty). Could be
the rubber boot around the door switch is crinkled up and keeping the
door switch pressed down (which keeps the switch in its open or break
condition). Does the dome light come on when you open the doors? You
could also look at the dash to see if a door is shown as open when you
open it (and the ignition key is on).

You could just forego the dome light and leave it off all the time.
Then just turn it on when you need it.

 

[VanguardLH]

May I be differ? LED current consumption is way less than a bulb. In the
range of miliiamps. Resistors main job is to drop the voltage at that
current draw. Overall LED will use way less energy(literally no heat).
Refresh your high school physics; Ohm's law. Look at the size of
resistor which is typically less than 1/2 Watt size which means?..... I
replaced all the illumnation on my patio in the back yard with LEDs.
They consume 1W each vs. bulbs which is ~7W and up.

Some configurations require a resistor in *parallel* to increase the
current draw. If you use LEDs for turn signal bulbs, you may have to
include a resistor in parallel for the flasher unit to work. Older
thermal-based flashers require a minimal current draw to heat their
bimetallic element that heats up to make contact and cools after making
contact to break the contact. In fact, the age-old problem of hooking
up trailer lights was the flasher would blink too fast because more
current was drawn through the thermal flasher unit which made it heat up
faster. See http://www.superbrightleds.com/carbulb-notes.htm. A load
resistor to increase current draw obviates the advantage of less current
draw for an LED.

If a timer does not rely upon the load to affect the timing then using
an LED in place of an incandescent will work (i.e., the circuit is timed
even if the bulb is blown). From what I've seen, dome light timers are
load dependent. Also to consider is that LEDs put out less light than
incandescents. That means you need more LEDs to generate the same
lumens as an incandescent. LEDs are directional in their light output
so a diffuser lens is needed or multiple LEDs need to point in multiple
different directions.

From what I read, the WRX should have a position for the dome light that
provides for an auto-delay shutoff. Perhaps the dome switch is in the
wrong position.

 

[clare]

Some configurations require a resistor in *parallel* to increase the
current draw. If you use LEDs for turn signal bulbs, you may have to
include a resistor in parallel for the flasher unit to work. Older
thermal-based flashers require a minimal current draw to heat their
bimetallic element that heats up to make contact and cools after making
contact to break the contact. In fact, the age-old problem of hooking
up trailer lights was the flasher would blink too fast because more
current was drawn through the thermal flasher unit which made it heat up
faster. See http://www.superbrightleds.com/carbulb-notes.htm. A load
resistor to increase current draw obviates the advantage of less current
draw for an LED.

If a timer does not rely upon the load to affect the timing then using
an LED in place of an incandescent will work (i.e., the circuit is timed
even if the bulb is blown). From what I've seen, dome light timers are
load dependent. Also to consider is that LEDs put out less light than
incandescents. That means you need more LEDs to generate the same
lumens as an incandescent. LEDs are directional in their light output
so a diffuser lens is needed or multiple LEDs need to point in multiple
different directions.

From what I read, the WRX should have a position for the dome light that
provides for an auto-delay shutoff. Perhaps the dome switch is in the
wrong position.

If the dome light is being left on, that ,means someone turned it to
the "allways on" position - so an automatic time-out system would not
help.
If you can't learn to shut off the domelight when leaving the car what
you need is a "battery saver" system that monitors the battery voltage
and shuts everything off when it gets below a certain point - which is
still enough to start the car..

These units are available from many automotive mass merchandizers,
like Canadian Tire in Canada.

 

[Bugalugs]

It's fun, isn't it?

Except having a recurring twitch from being zapped too many t-t-times...

Especially by the sparkplug wires !!!

 

[Carl 1 Lucky Texan]

Some configurations require a resistor in *parallel* to increase the
current draw. If you use LEDs for turn signal bulbs, you may have to
include a resistor in parallel for the flasher unit to work. Older
thermal-based flashers require a minimal current draw to heat their
bimetallic element that heats up to make contact and cools after making
contact to break the contact. In fact, the age-old problem of hooking
up trailer lights was the flasher would blink too fast because more
current was drawn through the thermal flasher unit which made it heat up
faster. See http://www.superbrightleds.com/carbulb-notes.htm. A load
resistor to increase current draw obviates the advantage of less current
draw for an LED.

If a timer does not rely upon the load to affect the timing then using
an LED in place of an incandescent will work (i.e., the circuit is timed
even if the bulb is blown). From what I've seen, dome light timers are
load dependent. Also to consider is that LEDs put out less light than
incandescents. That means you need more LEDs to generate the same
lumens as an incandescent. LEDs are directional in their light output
so a diffuser lens is needed or multiple LEDs need to point in multiple
different directions.

From what I read, the WRX should have a position for the dome light that
provides for an auto-delay shutoff. Perhaps the dome switch is in the
wrong position.

Mine has a 3 position switch.
I interpreted the OP to mean the light was inadvertently left on instead
of being put back into the center position.


Carl

 

[VanguardLH]

VanguardLH wrote:

Correction:

From what I've seen, dome light timers are load dependent.

Should've been "independent".

 

[Hachiroku $B%O%A%m%/(B]

Especially by the sparkplug wires !!!

Oh yeah! Find a bad plug wire in no time flat!