Footwell and Dome Light Circuit

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  • #1

    Footwell and Dome Light Circuit

    Hey guys,

    Here is the problem:
    -Footwell lights and domelight (door mode) will not turn on when doors are opened.

    What I know so far:
    -It is not the door switches, as the light on each door trim panel will come on when they are supposed to (I also asked Betty, she still knows when the doors open!).
    -The dome light is receiving power from the constant power pin, as it will come on when manually switched. I have not taken a meter to the power coming from the door circuit yet, I will test it when I get a chance today. That pin is obviously not getting power, but I would at least be able to see if any voltage at all comes through.
    -All fuses appear to be functional.

    I've been doing a lot of digging trying to figure this out. So far, the only thing I can think of is the TCU. But from my understanding, if that had failed, a lot of other functions would fail too. My wiper still works in all modes, and delay control for low setting still works correctly. The door key hole illumination also works fine. My defrost also works fine.

    Is there a separate unit that controls the dimmer circuit, or is it part of the TCU? I don't want to pull everything out to get to the TCU if that is not the problem, so I want to make sure I've checked everything else I can before that happens. Is there anything else that I should be looking for?

    Thanks in advance!
  • #2
    I think a diode under the driver seat?
    http://z31performance.com/showthread…2-2-(-now-NA2T
    My build thread (:
  • #3
    Man, I am having the exact same issue.
    I did replace the TCU, no change.

    Please keep this thread updated! I need this resolved.
  • #4
    Well, I guess it's bittersweet. I'm glad to hear I'm not the only one with this issue, but I hate that this is happening to others too!

    So a small update, I haven't done anything yet, but this morning I did notice that the light actually started working! Sort of…
    The footwell lights were starting to work, but they were very dim. I have very bright LEDs installed, so I know they were probably receiving less than half power. But here's the fun part, the fader circuit still works! I watched the lights fade away like they are supposed to. So now I'm thinking either a bad connection, or maybe some sort of power regulation to the fader circuit that has gone bad, and is now delivering less voltage.

    Question for those who still have it working, did the dome light fade as well? My dome light is still not working, even with the footwells kinda working. If it does not fade, I would guess a relay for the dome light that is not activating because it is not getting enough power, but I want to say I remember that the dome fades too…

    I still have to take a meter and see what voltage is actually being provided. And I'll be digging around the circuit diagrams to see if I can find anything there too.

    I just want everything working before Nismo Fiesta!!!
  • #5
    Diagrams

    Ok, so I found 4 related diagrams. I went ahead and rotated them for easier reading









    I see the diodes that les_joey_paul mentioned. I guess I'll start going through the circuit little by little until I figure out what it is!

    *EDIT*

    Forgot to put the location diagrams:





    Attached Files
    • Interior_Lamp_1.jpg (58.9 KB)
    • Interior_Lamp_2.jpg (79.2 KB)
    • Interior_Lamp_3.jpg (80.8 KB)
    • Interior_Lamp_4.jpg (60.8 KB)
    • Electrical_System_Location.jpg (94.1 KB)
  • #6
    I spent several hours last night trying to fix it.
    I give up.

    I am going aftermarket for the dome/foot lamps.

    Here is the module I bought…
    http://www.ebay.com/itm/161620807042
  • #7


  • #8
    Oh wow, you dove right in! lol

    The one on the ebay link seems like a good alternative to trying to figure out whats going on. My only concern is that it uses the ground as the switch, but the dome light switch used the positive (if I'm not mistaken). Of course, you could just re-pin the wires in the dome to have it switch ground, and you would be good to go with that module.

    I'm hoping to figure out what is actually wrong with it. By the way, do you know where the diagram is saying the diodes are? 110 and 108 (I have GLL), I can't tell if it's saying it's under the driver's side dash, behind the radio, or what…
  • #9
    I didn't go as far as diodes. Thats where I gave up.

    The TCU does send a ground signal to the lights. I tested this by grounding out the negative wire and all the lights turned on.
    That aftermarket one will fix this issue so easily.
  • #10
    So I have a somewhat similar problem to edwin86z. Replaced my footwell and door panel lights with LED's. Driver's side door panel light - put in LED, it worked. Thought it was loose, so bent the tabs a bit. Stopped working. Put in old bulb, nothing. Switched bulb holder with passenger side, nothing. Grounded the ground circuit to the body, light comes on. Connector lights up test light. Put old bulb in again, bent tabs more, cursed, pulled door panel off, can't find any bad wires, gave up. The bulb needs to be grounded via the circuit otherwise it won't turn off when the door shuts.

    Should have left them alone, it's a f'ing light behind a red reflector!

    The only thing I can think of is it's the connector to the bulb holder. But I gave up before testing it further.
  • #11
    Originally posted by Reds89 View Post
    So I have a somewhat similar problem to edwin86z. Replaced my footwell and door panel lights with LED's. Driver's side door panel light - put in LED, it worked. Thought it was loose, so bent the tabs a bit. Stopped working. Put in old bulb, nothing. Switched bulb holder with passenger side, nothing. Grounded the ground circuit to the body, light comes on. Connector lights up test light. Put old bulb in again, bent tabs more, cursed, pulled door panel off, can't find any bad wires, gave up. The bulb needs to be grounded via the circuit otherwise it won't turn off when the door shuts.

    Should have left them alone, it's a f'ing light behind a red reflector!

    The only thing I can think of is it's the connector to the bulb holder. But I gave up before testing it further.
    Switches on the car body side of the door, they have a circle rubber bumper that wears out. That is probably the issue here.
    Open the door and instead of sitting, loom down and to the right. You'll see it.
    http://z31performance.com/showthread…2-2-(-now-NA2T
    My build thread (:
  • #12
    I'll look more into it today. Reds89, your issue sounds like the door switch, as it grounds through that. The red light on the door trim is independent from the dimmer circuit, which is the issue that amreboot and I are having. I would test/replace the door switch and see if it helps.

    Amreboot, which wire/location did you choose to ground out for the circuit?
  • #13
    I tested the one from the driver side door foot light
  • #14
    Originally posted by edwin86z View Post
    I'll look more into it today. Reds89, your issue sounds like the door switch, as it grounds through that. The red light on the door trim is independent from the dimmer circuit, which is the issue that amreboot and I are having. I would test/replace the door switch and see if it helps.
    I don't have the fancy dimmer circuit like you guys have (I think). Door switches should be ok as I replaced the rubber covers several months ago with new. My door switch controls the footwell, dome, and door panel lights.
  • #15
    Okay, finished the test installation.

    Works great!
    Note - Video is still processing on youtube
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