# Adding LEDs to a Car



## underworldmagic (Nov 27, 2006)

Hi,

Wonder if any of you can help.

I would like to add some LED strips to my car so when the door opens the strips come on at the same time (just like the interior light). 

After doing some searching, it seems i have to find the wire which supplies power to the interior or side door lights which come on when i open the door.

I have located the bunch of wires under the drivers footwell, now i just have to find the right wire...

Ive searched some more and it seems a "multimeter" can assist in locating the right wire....anyone used one of these things, and how do you use it?

Thanks


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## SBM (Jul 4, 2013)

Not sure what car you have, but if there is a Haynes manual for it, it will tell you the cable, colour, pattern etc. or you might find a forum for oyur car and someone may have a manual in pdf for you for free.

Ben


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## underworldmagic (Nov 27, 2006)

SBM said:


> Not sure what car you have, but if there is a Haynes manual for it, it will tell you the cable, colour, pattern etc. or you might find a forum for oyur car and someone may have a manual in pdf for you for free.
> 
> Ben


I have a Mazda RX-8, Ive looked through the manual and it doesnt tell you. and unfortunately a Haynes manual doesn't exist for this car :wall:


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## PootleFlump (Jan 1, 2006)

get an automotive electrician to do this for you....


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## Lloyd71 (Aug 21, 2008)

This might be of some help to you. If not just join up and make another post in the right section and someone should be able to help you out quickly enough. I imagine you'd want to splice it in to either the puddle lights or the corner door lights.

Be careful with LEDs though, I replaced a load of my interior lights with 501 LEDs and they flicker slightly before dimming. It's not that noticeable but just a warning. :thumb:


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## underworldmagic (Nov 27, 2006)

Lloyd71 said:


> This might be of some help to you. If not just join up and make another post in the right section and someone should be able to help you out quickly enough. I imagine you'd want to splice it in to either the puddle lights or the corner door lights.
> 
> Be careful with LEDs though, I replaced a load of my interior lights with 501 LEDs and they flicker slightly before dimming. It's not that noticeable but just a warning. :thumb:


Nice one mate :thumb:

Thats a really useful post - I will join up and ask on that board if i have any problems.

I was planning on changing up my interior lights all to LEDs, thanks for the heads up.


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## happypostie (Jul 1, 2009)

ive got a vectra c and have led lights in my footwells , also in the boot , i also have had the whole dash done from vx amber to blue ,the footwells are easy to do , what i did was just bought some speaker wire and the leds from ebay , ( under a tenner will get the job done , and in any colour you want ) take the power from the interior light and run the wire down to the footwells ( or where you want them ) the leds only have 2 wires , so you really cant go wrong + and - .put 2 led strips in the boot and it is like daylight in there now .


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## underworldmagic (Nov 27, 2006)

happypostie said:


> ive got a vectra c and have led lights in my footwells , also in the boot , i also have had the whole dash done from vx amber to blue ,the footwells are easy to do , what i did was just bought some speaker wire and the leds from ebay , ( under a tenner will get the job done , and in any colour you want ) take the power from the interior light and run the wire down to the footwells ( or where you want them ) the leds only have 2 wires , so you really cant go wrong + and - .put 2 led strips in the boot and it is like daylight in there now .


Thanks mate - can I run all the LED strips from the same interior light?


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## danwel (Feb 18, 2007)

yeah don't see why not, you just need to find a power source and wire them up to the same relay that sets off the interior lights when you open up the door


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## Vote 4 Pedro (Jul 6, 2013)

What car do you have, 
I worked in an auto electrical workshop for over 20 years, mainly fitting car audio and alarm systems and the type of thing your doing.
left in 2002 but i still do loads of small jobs now and may know but it all depends on the make of your car.


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## underworldmagic (Nov 27, 2006)

Vote 4 Pedro said:


> What car do you have,
> I worked in an auto electrical workshop for over 20 years, mainly fitting car audio and alarm systems and the type of thing your doing.
> left in 2002 but i still do loads of small jobs now and may know but it all depends on the make of your car.


Thanks mate - I have a Mazda Rx-8. (2007)


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## Vote 4 Pedro (Jul 6, 2013)

I think mazda's have a green wire with a black tracer (stripe) on them to be found behind the kick well panel at the drivers side, this is your door open wire and should be used to earth your LED's and then you need a positive supply for the other wire, this is usually a white wire with a red tracer, this can also be found in the kick well.
Please test the wires first to be sure, if you have a test spike it's easily done


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## underworldmagic (Nov 27, 2006)

Vote 4 Pedro said:


> I think mazda's have a green wire with a black tracer (stripe) on them to be found behind the kick well panel at the drivers side, this is your door open wire and should be used to earth your LED's and then you need a positive supply for the other wire, this is usually a white wire with a red tracer, this can also be found in the kick well.
> Please test the wires first to be sure, if you have a test spike it's easily done


Thanks mate, really appreciate the help.

So the:

Black wire goes to the green wire with a black tracer
Red wire goes to a +ve power source - white wire with a red tracer

Can the power source be anything, or does it have to be to a source which comes "on" when the doors open (as i want the LED strips to come on when the doors are opened)

To test the wires first - how do you recommend doing that? would one of those electrictions screwdrivers work (the ones with the light in the handle, when theres power, the light comes on?) or a multimeter? Ive never used one, or know how to.


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## Vote 4 Pedro (Jul 6, 2013)

just thinking about it some more and the door switch wire (green wire with a black tracer) is sometimes a black wire with a blue tracer, different models and different age cars,
i think it's more likely in your age of car to be the Blue wire with the black line through it, 
and any positive will do for the supply as long as it's a constant feed, ie. on all the time regardless of the ignition or any thing else.
for the job your doing a very basic tester would be a wire with a crocodile clip at one end and then through a 12volt car bulb (usually 5watt) and then at the other side a sharp spike, about £2-£5 at an accessory shop
when your looking for a positive supply attach the croc clip to a good earth and the tester will light up when the spike touches a positive wire, and then to find an earth wire reverse it so attach the clip to a known positive supply and the tester will light up when a earth is found (by testing the wire you will have to stab the spike gently through the wire insolation) do not go anywhere near airbag wires under the steering colum


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## Vote 4 Pedro (Jul 6, 2013)

underworldmagic said:


> Thanks mate, really appreciate the help.
> 
> So the:
> 
> ...


Sorry mate i type very slowly...

The Red wire on your LED to a permanent supply, not controlled by anything.
and your Black LED wire to the cars door switch, this is a earth with when the door is opened, when the door is closed it is no longer an earth.
and the tester needs to be 12v so i don't think the screw driver tester you have will do because it sound like it's a mains tester.


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## underworldmagic (Nov 27, 2006)

Vote 4 Pedro said:


> Sorry mate i type very slowly...
> 
> The Red wire on your LED to a permanent supply, not controlled by anything.
> and your Black LED wire to the cars door switch, this is a earth with when the door is opened, when the door is closed it is no longer an earth.
> and the tester needs to be 12v so i don't think the screw driver tester you have will do because it sound like it's a mains tester.


LOL, no worries mate - i really appreciate your help, everything makes alot more sense now.

I found this:

http://www.ebay.co.uk/itm/CAR-CIRCU...931?pt=LH_DefaultDomain_3&hash=item4aa68ba2c3

Sound like just the think your talking about?

Using something like this, i assume theres no need to strip the wire a little, you would just "stab" the wire in order to touch the internal metal wiring.

Im thinking, it'll be good just to feed a distribution block from the mains battery into the footwell, then feed off the +ve power from there - it'll save spicing internal +ve wires, as im after 4 x led strips.

your thoughts?


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## petemattw (Nov 3, 2008)

wasn't there an issue on here with someone who replaced an interior light for an LED and it went up in flames?? I think there's a lesson here in not buggering around with things that aren't broken!


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## Vote 4 Pedro (Jul 6, 2013)

underworldmagic said:


> LOL, no worries mate - i really appreciate your help, everything makes alot more sense now.
> 
> I found this:
> 
> ...


That tester is just the job for testing the wires you need to, you would need a logic probe if you were going to be using one a lot, but this is ideal for this job,
It's a bit ott to use a distribution block for this but you could do if you like,
Just make sure that all wires are insulated properly after you have made your connections, If your running wires in your car be careful where you run them, make sure they do not obstruct anything or that they would get caught on anything, i'm only saying this because i don'y know you or how you work, safety first and all that. 
and adding LED light will not do any harm as long as you do it right.
I have fitted thousands with no problem, if you are unsure have a professional do it for you. but with a little common sense it's an easy job that most people could do.


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## underworldmagic (Nov 27, 2006)

Vote 4 Pedro said:


> That tester is just the job for testing the wires you need to, you would need a logic probe if you were going to be using one a lot, but this is ideal for this job,
> It's a bit ott to use a distribution block for this but you could do if you like,
> Just make sure that all wires are insulated properly after you have made your connections, If your running wires in your car be careful where you run them, make sure they do not obstruct anything or that they would get caught on anything, i'm only saying this because i don'y know you or how you work, safety first and all that.
> and adding LED light will not do any harm as long as you do it right.
> I have fitted thousands with no problem, if you are unsure have a professional do it for you. but with a little common sense it's an easy job that most people could do.


Thanks mate, your being alot of help.

Im really OCD when it comes to wires, I built my computer and a few others and the wiring is all cable tied inside for good airflow and looks : ) Ive also wired up my own sub, and managed to hide all the wires neatly. Car lighting is new to me.

For insulation on connections i was thinking of using some heatshrink.

Have you done undercar neons before? I want them on a on/off switch. Ive got an idea of the wiring, but not sure whats the beat way to run the wires...I think if i run the wires directly down from the battery to the side skirts/bumpers i will fail my MOT :wall: I know someone who did that to their Sub wire from the battery to their boot and failed (LOL)


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## happypostie (Jul 1, 2009)

underworldmagic said:


> Thanks mate, your being alot of help.
> 
> Im really OCD when it comes to wires, I built my computer and a few others and the wiring is all cable tied inside for good airflow and looks : ) Ive also wired up my own sub, and managed to hide all the wires neatly. Car lighting is new to me.
> 
> ...


ive also got under body leds fitted to my car , this was done via the battery , i have all the leds going to the box , and i have a kill button next to the battery , ( so that i can just push the button and with the remote they work , but ) can turn if off , so that they dont come on when driving . another easy job , im now looking at adding some blue leds into the wheel wells , but these will come on like the leds in the footwell , ( unlock the car , they will come on and stay on for the 30 secs, or so ) but as ive wired them into the interior lights they will also come on when the interior light button is turned on . .

:thumb:

Ive also done this to my daughters clio , a honda civic ( work mates )


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## Vote 4 Pedro (Jul 6, 2013)

If your using heat shrink you will have to cut the wires and thread the heat shrink on to the open wire, re-make the wire connection, solder the joint with a soldering iron, slide the heat shrink over the joints and use a heat gun on the heat shrink.

or you could take off about 1cm of the wire insulation from the cars wiring system (once you found the correct wire to be using)
and then take off about 2cm from the end of the led's wire to be connected.
wrap your bare led wires around the cars bare wire, solder the joints and then insulate the joint with black insulating wire or even better use self amalgamating tape, when you tape the join it's important to tape a few inches either side of the joint for support of the soldered join.
what ever you do don't use them !!!!!! scotch lock connectors.


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## Vote 4 Pedro (Jul 6, 2013)

Have you done undercar neons before? I want them on a on/off switch. Ive got an idea of the wiring said:


> yes i've done a good few, there's not much i haven't installed,
> I had my own Car Audio & Security business for over 20 years.
> 
> you would need to take a positive supply for your neons from a fused positive supply with-in the car or fit an in-line fuse as near to where you took the supply from, run the positive wire to a switch on the dash or a remote controlled sender unit would be better, if your going to use a switch it can look neater if you get hold of a factory switch and fit it into where you have a blank switch on your dash.
> ...


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## underworldmagic (Nov 27, 2006)

Vote 4 Pedro said:


> yes i've done a good few, there's not much i haven't installed,
> I had my own Car Audio & Security business for over 20 years.
> 
> you would need to take a positive supply for your neons from a fused positive supply with-in the car or fit an in-line fuse as near to where you took the supply from, run the positive wire to a switch on the dash or a remote controlled sender unit would be better, if your going to use a switch it can look neater if you get hold of a factory switch and fit it into where you have a blank switch on your dash.
> ...


wow, thanks mate :thumb:

Your advice has certainly educated me alot, there's alot I didn't know. Thank You.

Funny, i was searching and came a across the scotch lock connectors and thought "theyd be useful" LOL, lucky you told me, i'll avoid them now. Why are they so bad?


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## underworldmagic (Nov 27, 2006)

happypostie said:


> ive also got under body leds fitted to my car , this was done via the battery , i have all the leds going to the box , and i have a kill button next to the battery , ( so that i can just push the button and with the remote they work , but ) can turn if off , so that they dont come on when driving . another easy job , im now looking at adding some blue leds into the wheel wells , but these will come on like the leds in the footwell , ( unlock the car , they will come on and stay on for the 30 secs, or so ) but as ive wired them into the interior lights they will also come on when the interior light button is turned on . .
> 
> :thumb:
> 
> Ive also done this to my daughters clio , a honda civic ( work mates )


Thanks mate, wheel well lights hooked upto the interior lights - nice idea, maybe the next project when i get the hang of it :thumb:


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## Vote 4 Pedro (Jul 6, 2013)

underworldmagic said:


> wow, thanks mate :thumb:
> 
> Funny, i was searching and came a across the scotch lock connectors and thought "theyd be useful" LOL, lucky you told me, i'll avoid them now. Why are they so bad?


they are BAD BAD BAD, little [email protected][email protected]$ cause more electrical problems in cars than you could imagine,
iv'e seen it all when it comes to diy car electrics, most caused by scotch locks!!


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## underworldmagic (Nov 27, 2006)

Vote 4 Pedro said:


> they are BAD BAD BAD, little [email protected]@RD$ cause more electrical problems in cars than you could imagine,
> iv'e seen it all when it comes to diy car electrics, most caused by scotch locks!!


cool man, lucky you told me, i'll avoid them and stick to the old fashioned soldering :thumb:


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## Vote 4 Pedro (Jul 6, 2013)

underworldmagic said:


> cool man, lucky you told me, i'll avoid them and stick to the old fashioned soldering :thumb:


Anytime i can help, i don't know much but i do know about all that sort of suff,

Andy


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## underworldmagic (Nov 27, 2006)

Vote 4 Pedro said:


> Anytime i can help, i don't know much but i do know about all that sort of suff,
> 
> Andy


Nice one, im glad i "bumped" into you...you've been of great help. if i run into anything im not sure about i'll be sure to send you a message. You defiantly know your stuff mate, it shows. :thumb:

Some of the things you told me, i didnt even know existed "Self Amalgamating Tape" who would have thought LOL. Just been searching around, sounds like good stuff even to use around the house.

Thank again.


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## Lloyd71 (Aug 21, 2008)

underworldmagic said:


> Nice one mate :thumb:
> 
> Thats a really useful post - I will join up and ask on that board if i have any problems.
> 
> I was planning on changing up my interior lights all to LEDs, thanks for the heads up.


No worries, it's a really good forum for advice and help with RX8s. Replacing most of the interior lights is mega easy, and 501 LEDs are dirt cheap on eBay, I've done most of my interior, the boot and the number plate lights. The only problem I've had is the LED bulbs being slightly too big to fit in the map reader light units and that has caused the left one to come loose from time to time. It's easy to remove it from the roof and screw it back in though.

EDIT: Here's the difference mine made:


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## underworldmagic (Nov 27, 2006)

wow, thanks for sharing mate.

The difference is really noticeable, i never, i would have never thought my interior lights were _that _yellow! I will defiantly get mine switched in my rex.

Brake lights, i was planning on getting the spider led design LED cluster, thought that might look good, there seems to be plenty of space.


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## Lloyd71 (Aug 21, 2008)

underworldmagic said:


> wow, thanks for sharing mate.
> 
> The difference is really noticeable, i never, i would have never thought my interior lights were _that _yellow! I will defiantly get mine switched in my rex.
> 
> Brake lights, i was planning on getting the spider led design LED cluster, thought that might look good, there seems to be plenty of space.


I've got a cream interior in mine so the lights were really making the interior look yellow, the LEDs make a big difference of a night time. My brake lights are totally standard as they're apparently different on the Kuro, so thought I'd best leave them as they are. I posted the photo of the rear to show you the number plate bulbs as they're 501 LEDs, the same as the interior ones. :thumb:


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## danwel (Feb 18, 2007)

I got some cheap 501's off eBay too but went for blue just to be different. Not much use but look good lol


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## underworldmagic (Nov 27, 2006)

Lloyd71 said:


> I've got a cream interior in mine so the lights were really making the interior look yellow, the LEDs make a big difference of a night time. My brake lights are totally standard as they're apparently different on the Kuro, so thought I'd best leave them as they are. I posted the photo of the rear to show you the number plate bulbs as they're 501 LEDs, the same as the interior ones. :thumb:


Cool - ive got black leather interior so wont make the impact yours does (i would have loved cream)...well it'll brighten up my shoes LOL :thumb:

What color LEDs are in your footwell?


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## Lloyd71 (Aug 21, 2008)

underworldmagic said:


> Cool - ive got black leather interior so wont make the impact yours does (i would have loved cream)...well it'll brighten up my shoes LOL :thumb:
> 
> What color LEDs are in your footwell?


I don't have any in the footwell I don't think. If I do they will probably be the standard red ones like the ignition barrel light or the electric window control downlighters.


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