F355 dome light | FerrariChat

F355 dome light

Discussion in '348/355' started by bcar1, Feb 18, 2019.

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  1. bcar1

    bcar1 Karting
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    I’ve searched on the forum and google and can’t find anything so apologies if this has been answered already. My dome light does not come on and the switch does nothing- I assume the bulb is burned out but for my life cannot figure out how to remove it without applying so much pressure it feels like I’m going to break something. Is there a technique to remove the housing or dissameble it to remove the bulb?
     
  2. taz355

    taz355 F1 Veteran
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    Yes
    I think their is one ineither of the diy stickies
    Ie 348
    Or 355
     
  3. Dave rocks

    Dave rocks F1 World Champ
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    Very simple: cover the lens with painters tape then use a thin pry tool. There are 4 tabs, 2 per side. Very simple.
     
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  4. bcar1

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    Does the whole housing come out or just the lens?
     
  5. Dave rocks

    Dave rocks F1 World Champ
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    Just the lens.
     
  6. 490times

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    I'm down the rabbit hole with my dome light switch. Previous owner had an alpine "security system" tapped into the cigarette plug, the parking lights switch, and a variety of other things, along with a shock sensor self-tapping screwed into the floor pan. I ripped the security system all out, and everything still works except the dome light (which, to be fair didn't work before).

    The button has a white/black stripe wire which has constant power. A black ground, which is jumped to a second ground prong on the same button (Why?) And a yellow/red stripe wire which I imagine is the accessory that runs to the dome light when the button is depressed.

    I took a 12v light (with a 10amp inline fuse) which I tested and know works, hooked it up to its own separate ground, touched it to the white/black wire and it lights up... cool! So then I tapped the light's positive into the yellow/red wire to see if the switch works and it blows the fuse every time. Frustration.
     
  7. 308 GTB

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    This is a job for Qavion
     
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  8. Qavion

    Qavion F1 World Champ
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    #8 Qavion, Jun 21, 2020
    Last edited: Jun 21, 2020
    Sounds like your first problem. It shouldn't have power on it.


    The backlighting for the switch also needs an earth. Backlighting power comes in on the yellow-red wire. That's all the yellow-red wire is used for. Does the backlight work when you turn on your sidelights (via the steering column switch)?

    How many volts are you getting on the white-black wire?

    Hmmm... not really sure what's happening here. You may have to isolate various parts of the circuit. The interior light can be put on by the console button or by opening the doors. Does your interior light work with the doors? If the diode hasn't shorted, maybe your door light time delay module has a serious problem with it. You can unplug it and the interior light should still work with the console button. Conversely, you can disconnect your switch and the interior light should still work with your doors opening.

    A circuit diagram may help you, although it can be tricky to follow.

    Here's the diagram for a '95 F355

    F355 (2.7) Windows & Interior Lights

    Is your clock working?

    Actu
     
  9. Qavion

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    Or Miro :p
     
  10. Qavion

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    Sorry, had to edit my previous message (logic error). Does the black earth wire on the console switch actually go to a good ground?
     
  11. 490times

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    Thanks for the information and schematic. It's almost 230am but I'll give the wires another look tomorrow... I do know the door lights are working but can't remember if the button lit up or not.

    The clock does not work, lol, how did you know? I'll update asap tomorrow. Thanks again :)
     
  12. 308 GTB

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  13. Qavion

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    The interior lights, clock, doorlocks and door lights run off the same fuse (fuse 30) in the footwell. I don't know if you've blown the fuse as a result of your faultfinding. Are your doorlights still working?

    I'll try to think of more ideas while you catch up on your sleep )
     
  14. Qavion

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    #14 Qavion, Jun 21, 2020
    Last edited: Jun 21, 2020
    I'd forgotten how hard it is to get to the time delay module. It involves removing the forward luggage compartment liner and removing various components near the frunk latch. Only the 2.7 model has this time delay module. I believe that on the 5.2 car, the interior light time delay is handled by the immobiliser ECU.

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    Perhaps a last resort.

    Ignore that random comment about a diode in my earlier message (poor editing on my part).

    Were you checking power on the wires going to the switch with the connector plugged into the switch? Results may vary depending on whether the switch was plugged in or not.
     
  15. Qavion

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    If your fuse 30 is blown, it will be hard to track down the problem because it powers so many different things. Before you replace the fuse, switch off your dome light in every way possible. i.e. doors closed, console button off, overhead dome light switch off. Also switch off your map light if on. Then replace the fuse. Then progressively turn on the interior lights using the various switches and opening doors (to see if the fuse blows again). Sorry, I don't know if the overhead light switches on your car clearly show which switch position is OFF.
     
  16. 490times

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    Good morning :) the white wire had a tap in it to a 12v positive. I disconnected it and it's a step in the right direction!

    The dome light turns on constant when rocked forward (doors open or closed), and nothing in the middle or when rocked backward (doors open or closed). The console button does nothing that I can see in any of the 3 light positions...

    also, the clock and door lights are currently working after I replaced some blown fuses.
     
  17. Qavion

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    Ahh.. .you have a spider? So no map light? I don't have a diagram for a spider, so we'll have to improvise (I also have a spider)

    I had lots of problems with the switching on my light, so I just fitted a new one (it's also a Porsche part and still readily available). I'm not saying you have a light contact problem, but it's something to think about, especially as the light is not working with both the console switch and the door input.

    So, you have:
    power to the lamp (because it works by rocking it forward). Rocking back, it's off, I recall from my car.
    no response from the doors in the mid position
    no response from the console switch in the mid position.


    I guess if you have the switch out of the console, you could unplug the switch and test the internal switching. That is, use an ohmmeter to see if you get open and closed circuit indication when you move the switch). That is, put the ohmeter across the pins which correspond to the white-black wire and the black wire (when plugged in).
    Then you could check the white-black wire is continuous between the console switch plug and the dome light. I don't know if you've removed the dome light before to access the wiring? It can be tricky.

    Further actions require some further (more serious) disassembly.

    Unfortunately, now it's my bedtime (1:15am here)
     
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  18. Qavion

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    P.S. I hope the 12volts that was incorrectly on the white-black wire didn't fry your time delay module.
     
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  19. Qavion

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    I'm just wondering if your white-black wire is attached to your dome light?
     
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  20. 490times

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    Thanks again for your replies. I've found that rocking the light forward lights it up constant, doors open or closed. Middle does nothing. Rocking towards the back of the car gives power to the white/black wire with the doors open, and the button on the console still seems to do nothing in any position.
     
  21. Qavion

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    #21 Qavion, Jun 23, 2020
    Last edited: Jun 23, 2020
    I'm not sure why you're getting power on the white/black wire at any time. Perhaps it's the way you're measuring the power or there is an earthing issue.

    Anyway, I just checked my car and it seems my memory is a little faulty :oops:

    Lamp forward:
    Doors and console button work
    Lamp mid:
    No response from either input
    Lamp aft:
    Light ON

    This seems to agree with the manual (just checked for the Spider). Is there a chance your light assembly is mounted 180 degrees out?

    The console switch should illuminate the lamp (with the doors closed) if this is your door activation position.

    The lamp in the opposite position to this should give you the light on all the time. This uses power on the lamps orange wire and a permanent earth on pin C of the lamp (refer to the diagram). In all positions, there should be power on the orange wire on pin A (if tested with a voltmeter or test lamp, using a good earth on the car).

    I was thinking earlier that your door light time delay module was putting out a voltage (instead of an earth), but I think that would stop the lamp ever working (as you'd have volts on both sides of the lamp) and a short circuit if you put the lamp to fully on with the light in the the aft position (or forward position in your case). It may further damage the light time delay module doing this or perhaps blow fuse (30) and you'd lose your clock again.

    I'm not sure where to go from here without pulling your car to pieces. Because you have power on the BN (white-black) wire, it's not safe to do wiring resisitance checks. By the way, did you check that the console switch is ok when removed from the car? Alternatively, you could short out the
     
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  22. Qavion

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    (EDIT: Sorry, I did some last minute editing for clarity. Not sure if you read the last version.)
     
  23. 490times

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    I have an LED bar that I grounded and connected the positive wire to the white/black wire. When I rock the lamp backward, it powers the LED bar (that's how I deduced power is getting to the white/black wire without a voltimeter).

    I'd say theres a good chance my lamp could be mounted 180 degrees. I'm not sure what the OEM lamp was, but the one in there now is made by Hella so it could very well be aftermarket, seeing how the previous owner seemed to have a lot of fun with speaker and security wiring.

    I didn't disassemble or check the switch button internals yet, nor have I disassembled the lamp. When I get back from out of state in a couple days I'll dig back into it :)
     
  24. Qavion

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    No need to disassemble the switch, just get access to the rear of the switch and the plug.

    Ah, if your lamp wiring was still connected to the lamp and you put your LED bar on the white/black wire pin on the lamp, then you may simply have been getting normal 12volt power through the dome lamp to your LED bar. Something like this.

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    If you subsequently got an earth from the console switch or the doors time delay module, the LED bar would extinguish in this case.

    If you disconnect the lamp and put the LED bar on the white/black wire, does the LED bar illuminate?

    I'll try and create a series of diagrams to simplify the circuit.

    I can't remember if the terminals on the dome light are identified. Is it possible to get them mixed up?
     
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  25. Qavion

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    Sorry, that diagram is not quite correct... This one is a little closer....

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    You just have to imagine that the switches can't be closed at the same time.
     
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