DIY: Trunk lighting for spare tire owners.
04-04-2004, 06:00 AM
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Lubricious
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Trunk light for spare tire owners.
If you have the spare tire kit you know that the stock trunk light is virtually obliterated by the tire. I decided to get some additional lights.
What I found were "LED Light Fixtures" from autolumination.com. These are small fixtures with 3 LEDs each, with about a 100 degree spread. They're cheap so I purchased 4 because I couldn't be sure how bright they'd be. I ended up only using 2.
Here's a pic of one of the fixtures. I chose the "white" output version.
What I found were "LED Light Fixtures" from autolumination.com. These are small fixtures with 3 LEDs each, with about a 100 degree spread. They're cheap so I purchased 4 because I couldn't be sure how bright they'd be. I ended up only using 2.
Here's a pic of one of the fixtures. I chose the "white" output version.
04-04-2004, 06:01 AM
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Lubricious
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The switch that controls the trunk light is built into the lock. It's the topmost connector, with the brown and black wires. Note - the plastic trim was removed prior.
04-04-2004, 06:03 AM
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The fixtures come with long leads and I experimented for a while, affixing with masking tape to find good locations. I decided on some recesses on the left and right sides of the trunk. These points aim the light nicely into the well and does not result in an objectionable amount into the eyes when you're standing over the trunk. I reamed a small hole in the lining to pass the wires through. Here's the fixture with the adhesive backing partially removed and getting ready to feed the wires through the hole.
04-04-2004, 06:04 AM
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You've got to remove some more of the little plastic anchors so you can move back some of the liner to get to the backside. Here's the left side with the fixture's wires coming through. The adhesive seems more than strong enough to stay attached to the liner permanently. Having the liner away from the panels gives you a good chance to press down firmly against the adhesive of the fixture and get a good bond.
04-04-2004, 06:06 AM
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Similarly on the right side of the trunk. Hard to see but I am using some "Marine Goop" to immobilize the wires where they pass through the liner.
04-04-2004, 06:08 AM
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Here's a picture of all that crap taken with no other light but what the LEDs are putting out. It's a fairly long exposure but gives a good idea of the relative lighting intensity.
04-04-2004, 06:10 AM
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Oh! Back to the how-to. Both of the "+" wires from the LEDs are connected in common with the black wire as it exits the switch connector. This gives them current only when the switch is on.
The black wire is then snipped downstream of this attachment. This is necessary because otherwise the OEM trunk bulb retains a direct path to ground. This means it lights up with its normal brightness and also means that the voltage drop is too severe to get any output from the LEDs. By snipping the black wire you're then forcing the OEM trunk light's current to have to pass through the LEDs on the way to ground. Since the LEDs are vey low current devices, the OEM incandescent bulb doesn't get hot enough to increase resistance very much. It just glows a feeble brown (barely on). I suppose I could short across it to prevent any loss but at this point I'm satisfied with the light output.
I hope this picture isn't too cluttered to explain it
The black wire is then snipped downstream of this attachment. This is necessary because otherwise the OEM trunk bulb retains a direct path to ground. This means it lights up with its normal brightness and also means that the voltage drop is too severe to get any output from the LEDs. By snipping the black wire you're then forcing the OEM trunk light's current to have to pass through the LEDs on the way to ground. Since the LEDs are vey low current devices, the OEM incandescent bulb doesn't get hot enough to increase resistance very much. It just glows a feeble brown (barely on). I suppose I could short across it to prevent any loss but at this point I'm satisfied with the light output.
I hope this picture isn't too cluttered to explain it
04-04-2004, 06:14 AM
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and facing the driver's side. The LEDs on this side are not quite as blue or bright. Since I bought 4 fixtures I probably should have spent more time trying to match a balanced set. But overall it works pretty well.
04-04-2004, 06:15 AM
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Caveat - when I bought these they were advertised as consuming 20 mA of current. Now the page says 60mA. I don't know if the fixtures have changed or if the initial spec was mistakenly just giving the figure for a single LED of the set. And, I'm too tired to go back out and test one for current
zzzzzz
(edit - tested one of my spares and it's drawing 40mA at 12.5 volts. go figure).
The issue is that if the current draw rises appreciably, the stock OEM bulb will start to heat up to where its resistance would be a factor drawing down the voltage to the LEDs. This could be eliminated though, by shorting across the OEM socket or connector.
Since this is a change to the electrical system I have to say - try at your own risk. Void where prohibited. Do not taunt happy-fun-ball.
EDIT: one last thought - it might be smarter to wire the lights and cables to pull-apart connectors so that if you need to remove the liner at some future point, you can do so easily. I guess I'll just wait until the need arises.
(edit - tested one of my spares and it's drawing 40mA at 12.5 volts. go figure).
The issue is that if the current draw rises appreciably, the stock OEM bulb will start to heat up to where its resistance would be a factor drawing down the voltage to the LEDs. This could be eliminated though, by shorting across the OEM socket or connector.
Since this is a change to the electrical system I have to say - try at your own risk. Void where prohibited. Do not taunt happy-fun-ball.
EDIT: one last thought - it might be smarter to wire the lights and cables to pull-apart connectors so that if you need to remove the liner at some future point, you can do so easily. I guess I'll just wait until the need arises.
Last edited by Nubo; 04-04-2004 at 04:43 PM.
04-08-2004, 07:51 PM
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Nubo, excellent work! This was one of the small upgrades that I have had in mind since the first time I opened the trunk and was in disbelief that Mazda didn't relo the light as part of the spare tire kit.
My wiring plan was a bit different and would like your input. I was planning to pop out the existing light since it is already at the end of the switched circuit and use a couple of inline splices to wire the additional lighting fixtures in parallel to the existing light.
Is there some reason you didn't do it this way? Is there some reason that this way wouldn't work?
My wiring plan was a bit different and would like your input. I was planning to pop out the existing light since it is already at the end of the switched circuit and use a couple of inline splices to wire the additional lighting fixtures in parallel to the existing light.
Is there some reason you didn't do it this way? Is there some reason that this way wouldn't work?
04-08-2004, 08:47 PM
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Originally posted by beachdog
Nubo, excellent work! This was one of the small upgrades that I have had in mind since the first time I opened the trunk and was in disbelief that Mazda didn't relo the light as part of the spare tire kit.
My wiring plan was a bit different and would like your input. I was planning to pop out the existing light since it is already at the end of the switched circuit and use a couple of inline splices to wire the additional lighting fixtures in parallel to the existing light.
Is there some reason you didn't do it this way? Is there some reason that this way wouldn't work?
Nubo, excellent work! This was one of the small upgrades that I have had in mind since the first time I opened the trunk and was in disbelief that Mazda didn't relo the light as part of the spare tire kit.
My wiring plan was a bit different and would like your input. I was planning to pop out the existing light since it is already at the end of the switched circuit and use a couple of inline splices to wire the additional lighting fixtures in parallel to the existing light.
Is there some reason you didn't do it this way? Is there some reason that this way wouldn't work?
05-05-2004, 01:35 AM
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Originally posted by femtochemistry
Good work.
żDoes blue and white ligths the same intensity?
Good work.
żDoes blue and white ligths the same intensity?
Well, both fixtures were sold as "white". It turns out that one is somewhat brighter and has a bluer tint than the other but not different enough to be annoying. I actually bought 4 fixtures and if I were to do it again I would have compared the 4 more closely to get as closely matched set as possible.
I suspect if you bought a "blue" set, it might be harder to distinguish objects in that light even if it were rated as the same brightness. Visual discrimination seems easier in multi-spectrum light than in monochromatic light.
06-15-2004, 08:28 PM
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Nubo, I finally got around to adding the trunk lights. I used your wiring method after all. Chose different locations for the lights. I used the metal cross member across the top of the trunk and snaked the wires through existing holes. Interesting thing though, my oem trunk light isn't lighting at all, not even a bare glow. I'm going to drop the spare tomorrow and take the bulb out.
Not enough light to read a book, but at least I can find things and if I ever need to get to the tools at night I don't need to fumble with a flashlight in one hand.
Here are a couple of crummy pictures taken w/my phone just so you can see where they are located.
Not enough light to read a book, but at least I can find things and if I ever need to get to the tools at night I don't need to fumble with a flashlight in one hand.
Here are a couple of crummy pictures taken w/my phone just so you can see where they are located.