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HELP: Sidelights & Just One Taillight Not Working

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I was running a little project of using a sidelight bulb holder into red/black wire to run wiring into the cabin for some footwell lighting (501 halogen not led). So that the footwell lights came on with the lights.


All the wiring was done and i tested out the wiring going straight to the battery and it worked perfectly. I then plugged them in to the passenger side sidelight holder wiring and they didnt work. I then checked other bulbs and my licence plate bulbs and ONE of my taillights are not working. The passenger side taillight still works, but not the drivers side! I checked the fuse in the engine bay near the battery and it was fine. When i removed this fuse the passenger taillight obviously went off, then when i reinstalled the fuse that one taillight came back on.


I replaced the drivers taillight (with a spare one) just to triple check it wasnt the light unit, and same result with the other unit. I also plugged in two normal sidelight bulbs and nothing...


So this has left me very confused and i cannot get my head around it....


How can it appear that some of the circuit (the passenger taillight) is still working but the other lights (that i believe are all on the same circuit) are not working?


Any advice would be really greatly appreciated! Im hardly driving atm and not at night, but i still want to get this resolved asap!


This is a picture of the sidelight adapter i used (i only used one of the drivers side sidelight). Which is pretty straight forward and should be fine to use (they are used for led halo sidelight wiring a lot).



Edited by davidv10
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Hi @davidv10, looking at your two adapters I notice their contact wires aren't bend in an identical fashion; might one of them simply not give electrical contact when plugged into one of your T10/168 sockets (front parking light, or rear license light? Swap over the adapters on a working light and see if the other suddenly doesn't work anymore. Can't think of any other good reason, given that the fuse is fine.

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Thanks for the reply!


I have since removed the adapter and replaced both sidelights with normal T10 bulbs. And still nothing is working other than the passenger side taillight. So i must have blown/damaged something if back to stock there are lights still not working?


Are both tail lights on the same circuit? Is there a relay or fuse or something between them causing the damage/blown something to be after the power to the passenger taillight?


Also, do you know where the tail light relay is, and can it be removed/replaced?


Sorry for all the questions!

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Can u specify which bulb of the driver side tail light isn't working anymore? Is it the turn signal or reverse light? I'd expect each tail light to have their own fuse, so that when one side fails the car can still drive with the other side working rather than all being pitch black.

there might be more fuse to be checked. There are fuse boxes by the gas pedal, too. Pretty sure it's merely a matter of finding that blown fuse and all should go back to normal

Edited by V1H
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So the specific lights that arent working are:


- Both Front Sidelight Bulbs (now stock bulbs)

- Both Licence Plate Bulbs

- Drivers Tail Light Sidelight LEDs


All the rest of the drivers tail light bulbs (indicator, reverse, brake lights) are working fine. Its just the sidelight LEDs that arent.


The passengers tail light sidelight LEDs are working fine.


Thanks for your continued help!

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Thats for a 350z unfortunately.


This is the 370z fuse box below. The arrow points to the normal TailLight/Illumination fuse which i believe is for the front and rear sidelights and license plate bulbs. Thats the one i checked and it was fine.



When i pulled that fuse out, the passenger sidelight went out. So that means that there is power going through that fuse fine. Then when i reinstalled it the passenger sidelight came back on as expected.


So thats why im thinking there has to be a relay or something further down the line that is causing the issue for the other bulbs?


The service manual references a tail light relay. Does anyone know where this is located?


Thanks again.

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Yeh its a really @*!# issue to have. Having a single corner sidelight being the only one working just makes no sense and has no logic...


I have the car booked in at Abbey on Thursday for the EcuTek remap, so ive emailed them to see if they can take a look at the same time. So fingers crossed!

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The problem has been fixed! It turns out that it was a fuse, but not to do with the Tail/Illum fuse. It was the 'Clearance' fuse (how was i supposed to guess that by the name :shrug:).

I was probably being naive not to just check all the fuses in the fuse box, regardless of their name. So i hope this thread can help others in the future if this happens to them.


Apparently one rear sidelight runs on a different circuit for safety reasons (so not all lights will go out at once), which makes sense and explains my issue.


Thanks for all the help guys!


Feel free to close the thread :)

Edited by davidv10
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