Overly sensitive LED light?

[Lolvoguy]

ON the Focus in the sig, I recently replaced the interior dome light with a red LED to:
1) reduce eye fatigue when opening the door
2) try something different, cause it was cheap

Anyway, since replacing it a few weeks ago, last night when returning from purchasing groceries, I noticed that when it's in the "door" position (and doors closed), it gives off a very small amount of light. Only when in the "off" position, is it truly "off".

The dome light operates on a dimming circuit. At first I was concerned that it was killing my battery when the car is off. Then I realized that it's probably picking up the tiny current that it's fed, when it's supposed to be off.

I never noticed this when using the traditional style of incandescent bulb in that place. Then again, that bulb requires more power to run and generates considerably more heat!

Should I be worried? or am I concerned for nothing?

thanks in advance

 

[SHOZ]

Some LEDs do this.

 

[440Magnum]

It because the dome light is actually controlled by the computer via CANbus on that vehicle. There's always a small voltage applied to detect if the bulb is there or not. You might discover that it does other stuff "wrong" too, like not dimming, not coming on sometimes, etc.

You can get CANbus-compliant LED dome bulbs that will truly go off when off, or you can solder a resistor in parallel with the CANbus bulb. I think the recommended value is somewhere around 1K ohm for interior bulbs, but I'm not certain on that.

 

[SwampSurvivor]

Superbrightleds sells canbus compliant LEDs.

I have been considering buying a few for various things in the Focus - such as ceiling and trunk lights, but don't want to confused the CANBUS.

 

[HTSS_TR]

My Volvo has the same problem, but not S2000 and E430. I didn't change to LED bulbs for Accord yet.

 

[Jetronic]

fit a pulldown resistor and this issue is no more.

 

[Lolvoguy]

Originally Posted By: 440Magnum
It because the dome light is actually controlled by the computer via CANbus on that vehicle. There's always a small voltage applied to detect if the bulb is there or not. You might discover that it does other stuff "wrong" too, like not dimming, not coming on sometimes, etc.


no, this seems like the only issue. aside from that it seems to operate normally

 

[Carmudgeon]

I had the same issue on a pre-CANBUS vehicle. I thought it might have been the light module leaking current, but it's more likely to be the aftermarket alarm, which monitors the interior light circuit as one of its triggers.

In any case, a 10 cent 1k ohm resistor placed in parallel in one of the interior lights on the circuit took care of the minor issue.

Vehicles engineered only with incandescent bulbs in mind can result in odd things like this, or polarity issues.

 

[razel]

Happens in my car as well. LEDs in the doors. If it's dark and I close the door I see a very dim light. I lock the door, it goes away. I'm guessing in my case it's because of the courtesy bulb dimmer. The overhead light slowly dims after you have closed the door. I'm guessing there's stored energy somewhere. What's surprising is if I don't lock the door and leave the LEDs dim it can take more than 12 hours of that energy to dissipate. I never actually tried to test when it goes out, but I have yet to have a dead battery because of it. Some of these LEDs are that energy efficient. I'm sure those in the very poor third world loves em.

 

[Lolvoguy]

Just got back from a trip where the car was left at home. It wasn't run/ started in about 6 days

Sure enough, went to start it and no issues.

guess it's nothing worth worrying about

thanks again guys!