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pheonix68
09-24-2017, 10:47 PM
Hi everyone.

I'm new to a forum, I'm from Canada and just bought a 2014 fiat 500e.
I was wandering if some of you encounter problem with dome light voltage?.

Without any light I get my 12v but as soon I put a led bulb the voltage drop to around 8 to 6 volt so I don't get the brightness that I should.
I try bulb that say Canbus and worse they don't light up.
I try the dimming but it say not available

Thanks and have a good day everyone.

forby
09-24-2017, 11:46 PM
Led Bulb? Is it OEM or something you bought on the internet. LED bulbs need a resistor to replace regular bulbs.

rkw
09-25-2017, 12:09 AM
Without any light I get my 12v but as soon I put a led bulb the voltage drop to around 8 to 6 voltI don't understand what you are trying to say. Please rephrase with a clear description of exactly what you did.

I installed LED bulbs in my dome light and have no issues.


LED bulbs need a resistor to replace regular bulbs.That's only true for exterior bulbs, and it would still work with no resistor, just that the dash would display a bulb out warning.

pheonix68
09-25-2017, 12:23 AM
When I bought the car they was led bulb in the dome light but it was really dark, so I got other led bulb, I check the voltage at the connector without bulb and the voltage was 12v but as soon that I put a led bulb the voltage at the connector drop and the bulb is not on.

mattjk
09-25-2017, 01:39 AM
http://www.fiat500usaforum.com/showthread.php?26192-Found-the-perfect-sized-LED-panel-for-the-500

forby
09-25-2017, 02:03 AM
When I bought the car they was led bulb in the dome light but it was really dark, so I got other led bulb, I check the voltage at the connector without bulb and the voltage was 12v but as soon that I put a led bulb the voltage at the connector drop and the bulb is not on.
sounds like you bought a bulb with the wrong voltage. It's eating up the power.

pheonix68
09-25-2017, 02:05 AM
I put that kind of panel but don't get that brightness because the voltage doesn't stay at 12 volt, I got the same issue with the truck light too. Can't find out what make the drop of voltage on the circuit when I put led light.
I try to disconnect the battery and reset to factory but nothing.

rkw
09-25-2017, 02:29 AM
Try a standard (not LED) bulb like the original C5W or equivalent. It won't be bright (that's why people replace them), but it shouldn't be unusually dim either. If it's very dim, then there's something wrong with the circuit in your car.

pheonix68
09-25-2017, 02:43 AM
That's what I'm going to do and I just bought the PDF version of the service manual with all with all the wiring diagrams and diagnostic, to try to pin point the problem.
Thank you everyone.

pheonix68
12-17-2017, 03:29 AM
Small updated on the problem, The problem came from the body control module. the last owner install HID headlamp and they created a feedback loop an probably created a short inside, When I unplug them and re plug them they stop working. I got a new BCM and all the light start working correctly. So guy's be careful, BCM is the weak part of the car.

forby
12-18-2017, 06:12 PM
Sounds like you put in the wrong kind of LED bulb (even if it fits)

pheonix68
12-19-2017, 02:24 PM
For the dome light It's was my first guess but it was nothing to do with led. if I put the regular bulb it won't light up because it create a short. I found out that the HID light bulb system that was install pull more power at the beginning. So it stress the circuit of the BCM. I read that it's safer to put a relais kit, this way you pull minimum of power from the BCM but it was to late for me, BCM was already affected when I bought the car and in Canada they are no warranty