My New & Improved LED Trunk Light

[kenmce]

I have known for a while that the stock Gen. II trunk light rates somewhere between "sad" and "pathetic". Went out this weekend and finally did something about it.


The culprit:



(Stock light inside left rear of car. Silver switch is not stock.)

I pulled out the stock light and tapped into its wiring to get power. This light has power any time the trunk is open and does not when the trunk is closed. It doesn't matter what the rest of the car is doing. You remove the light by prying the side with the switch.

(light out)

I peeled back the insulation on the positive wire, wrapped my new wire around the existing one and soldered them together. I then led it over to the new switch. The negative wire and the new switched positive both run down to a current regulated power supply. The current regulator takes in the wavery, irregular voltage from the car and puts out a steadier current that never overdrives the LEDs. Overdriving them would burn them out. The one I used is by a company called AsianSignals.com. I padded mine so it won't rattle and tucked it in behind the liner.




(Board uses surface mount components, is both inexpensive & small. Pictures of current regulator courtesy Asiansignals.com.)

From the current regulator a wire goes up along the side of the trunk rim, over the back of the ceiling liner, up through the rubber cable guide into the trunk lid, and then to the light.


(Close up of section of Striplyte courtesy acolyteled.com. You are looking at the front of the unit.)

The light I chose is a Striplyte™ 50 LED 12 Volt DC White 5500K. It is about an inch wide by almost a yard long and has a string of cool white SuperFlux LEDs running down one side. I *think* I'm getting around 130 lumens out of the stick. I went with this unit because I have dealt with this company before and consider their lights to be of extremely high quality. I could probably get something cheap that looked similar from China, but they just don't have any emphasis on quality at this time. You can inspect the insides of the light through the epoxy and everything is done the way I would do it, no corners cut. The striplyte (I hate that cutesey name) comes in a clear plastic mailing tube. I took the labels off the tube and and zipcorded the tube to the inside of the trunk lid to house the light.



(Hatch liner laying in trunk, clear mailing tube zip corded to liner, new power cord runs through new hole in liner)

I took pictures of the trunk as seen by the new vs. the old light. The pictures came out awful and I wound up having to fake them to show approximately what the eye sees. A side effect of the operation is that you do not block the light from what you are working on by reaching for it with your hand. The new light is diffuse and just goes around.


(Simulated old light)

(Simulated new light)

The new light also does a trick. When I wired it up I put on a cord that is ten foot longer than it needs. When the lid is open I can slide the light sideways out of its tube and now I have a tethered flashlight for working around the back of the car. I drilled a hole in the liner and the extra cord stuffs into the inside of the hatch when I don't need it.

(New light standing on ground outside car)


(New light as seen from passenger seat)



Summary:

Difficulty: Modest.

You need to collect up the bits, wire them together in proper order, hide wires behind the upholstery (I used ordinary lamp cord), put crimp fittings on the wires, and I did a little soldering to join into the wiring harness without cutting the stock wire.

Cost: Modest.

The light stick goes for around $50 ~ $75 US. They come in various colors. I went with cool white because it's the brightest. The current regulator is around $ 13 US. The lamp cord, switch, and terminations came to maybe $10 US or so.

[macmaster05]

That is one cool mod. I'd probably never do something like this, however, to avoid risking electrical fires.

Oh and next time try to resize your images. You nearly crashed my browser.

[patsparks]

Great project but so hard to look at the pictures and read the text. Can you resize the pictures please?

[kenmce]

macmaster05:
That is one cool mod.

Thank you.


I'd probably never do something like this, however, to avoid risking electrical fires.

Let's consider it from a safety point of view. We'll start with the image below:



The two lines on the far left are where I tie into the existing wiring. Not shown is the factory fuse, which covers my bits the same as Toyotas. From there the current goes to the switch, then the regulator, then the light. When the trunk is closed there is no potential current in any part of the system. When it is open there is potential current up to the switch. If the switch is on then the circuit is energized. When running, the whole thing uses ~four watts, about the same as a dome light.

What if something fails? There are two basic ways an electric circuit can fail, open or closed. "Open" means that current is not flowing, even if it should. "Closed" means that current is flowing, possibly somewhere you don't want it. This would be called a "short" or "short circuit"

If anything in the installation fails open, the light will no longer have power, and it will stop working. The power doesn't pool up anywhere. When the current can't flow it has no ability to do work and it is not able to create heat or cause shocks or do mischief.

What if something fails closed? If the switch fails closed then I won't be able to turn off the light with the switch. No big deal. If the current regulator fails, but continues to let current through, I might overdrive the light. This might cause it to die young, but would not hurt anything else. What if the light failed closed? It would consume power (when on) and perhaps produce heat instead of light. It can't produce a lot of heat, because it doesn't have that much power. If it did sit there warming itself it is reasonably placed to air cool until someone notices it. It can't sit and drain the battery because it still has no power when the car is closed up.

What if there is a short, say one of my bits to the body of the car? This would give you a good electrical connection, electrons would begin to race, and the fuse would blow. End of story.

In summary, I think the safety of this is comparable with the safety of the stock light, and if anything fails, it is unlikely to affect anything farther away than the fuse.


Oh and next time try to resize your images.

Done (?)

[car2lvr]

To play safe add an inline fuse with proper fuse rating. Just in case you have a short, the current path will be cut off.