Hi everyone,

My Fabia estate boot has a disappointing light and so I bought a W5W one sided LED so it can be positioned with the illuminated side pointing into the boot space. 
All went well with the installation and it was nice and bright with the boot opened. 
However, on shutting the boot or activating the latch with a screwdriver, the LED dimmed lots but did not quite go out. 
I replaced the standard W5W filament bulb into the holder and no problem, it’s either on or totally off. 
So what is going on? The boot latch is only a year old and there never seems to be a drain on the battery even if I don’t drive the car for a couple of weeks. 

This happens sometimes with LEDs. It's like it holds a tiny bit of residual power but it doesn't actually draw any power. I have the same issue with my OH's Hyundai when I replaced the main courtesy light.

8 minutes ago, petrolcan said:

This happens sometimes with LEDs. It's like it holds a tiny bit of residual power but it doesn't actually draw any power. I have the same issue with my OH's Hyundai when I replaced the main courtesy light.

Thank you for your reply. 
Does your LED eventually go out as e

I would have thought that any residual power will be used up eventually?

Edited 22 June, 20223 yr by prt57

It is not residual power, Mr Newton were he still alive would have told you that such a notion is BS.

 

Usually its the bulb filament monitoring circuit, not so sure on a boot light so more likely the tiny collector leakage current on the switching transistor.

 

You can use a high impedance shunt resistor to get rid of the glow.

 

The same current would have been passing through the incandescent bulb but nowhere near enough to create visible light.

Edited 22 June, 20223 yr by J.R.

Yes, there is no reason to suspect that the current is behaving any differently in either the bulb or the LEDs. 
 

However, I have basic LED Halfords W5W sidelights in my headlights and when the lights are switched off the illumination disappears not just very dim. 

1 hour ago, prt57 said:

Thank you for your reply. 
Does your LED eventually go out as e

I would have thought that any residual power will be used up eventually?

 

I honestly don't know in that I've never bothered checking. I know the wee bit of light left isn't enough to illuminate anything and we've never had a battery issue.