I have replaced the interior light bulb with an LED one and when I have the switch in the centre possition, it is illuminated all the time. It is only dim but it is definitely on. When I open the door it comes on fully and when I close the door, it dims as per a normal festoon bulb but it does not go off completely. Is there any particular reason for this or is it purely due to it being an LED replacement? I'm not worried about my battery going flat as it is such a low power drain but am interested to know what is happening. I did put a standard bulb back in and that switches off. Is it because there is always current flowing through it but on a fillament bulb, there is not enough to make it glow, but on an LED it is enough to make them glow slightly?

Hi,

yes it sounds like as you mentioned . Any one LED needs 10 to 20 milliamp for full brightness ,whereas a 10 watt filament lamp takes 0.83 amp (or 833 milliamp)when on. The interior light is switched by electronics,and not a mechanical switch or relay ,as older cars have. Proved by the fact the light fades away slowly when turned off). It seems there must be a small current flowing when light is off,enough to semi light the LED,but not enough to light the original filament bulb. You could try a low value resistor across LED to 'steal' the current,or just put up with it! . I am against anything extra other than radio,clocks etc, that permanently drains the car battery. If the car is used infrequently like mine , the battery can be nearly flat ,when needed to start the car.

Edited 21 February, 201016 yr by AndyPandy