Good afternoon, wonder if anyone has came across this before. 
Have just changed the interior 501 bulbs to LED ones as i thought the ones fitted were poor. The LED ones are a massive improvement, but just noticing that when you lock the car they are glowing slightly. The ones i ordered said they were canbus error free, which i presume means they have a built in resistor. 
Have left the car for about 15 mins now and it looks like they’re still glowing away. Not sure if they will sit glowing away all night and drain the battery although i imagine the current that is required to light them is minimal. 
The bulbs were just off ebay. 
 

Any ideas? 

There is a constant current running through the lighting system, even when the car is locked and most modules have shut down. I suspect the CANBUS system uses the door switches (that turn on the interior lights) to monitor / operate the alarm in case of activation. With the original halogen bulbs this minimal current wasn't enough to light the filament.

 

The factory fitted LED interior light units are sealed and are likely configured to work properly on a CANBUS system. I guess the bulb manufacturers interpretation of 'CANBUS compatible' might be different to that of Skoda's?

 

Some LED bulbs contain capacitors that hold residual energy after the power has been cut, but if this were the case they should stop glowing after a few hours as the energy in the capacitor depletes. If they're not then chances are the source of power is coming from the car and not the bulb.

 

Not as cheap as retrofitting LED bulbs, but if I really wanted the benefits of LED interior lighting I think I'd be looking to source the original OEM light units.

 

 

39 minutes ago, silver1011 said:

There is a constant current running through the lighting system, even when the car is locked and most modules have shut down.

Incorrect

39 minutes ago, silver1011 said:

I suspect the CANBUS system uses the door switches (that turn on the interior lights) to monitor / operate the alarm in case of activation.

Canbus does not monitor bulbs, it is the communications protocole between modules one of which (various names, comfort control, body control module etc) will monitor external bulb filaments, the alarm module may monitor the interior lights but probably simply the battery voltage drop. When the doors are closed and locked there is no current through the interior lights after the courtesy delay.

 

It's possible that the delay is a resistor capacitor timing circuit using the bulbs as the resistance but were that the case the LEDs would be fully lit for the extended period.

 

15 minutes is not long enough for all the systems to go to sleep and I reckon if the OP looks after 30 minutes or an hour the glow will no longer be present.

CAN-BUS is the nervous system of the car, sure it relies on the various modules, but CANBUS connects these modules, so CANBUS does monitor the bulbs, albeit via the BCM or CECM etc.

 

Various CAN-BUS controlled modules remain live long after the engine /ignition is turned off. There are various features and functions that remain awake for longer periods, those features and timings vary by manufacturer and model.

 

Posts around glowing retrofitted LED's remining lit at all times (often all through the night) suggests that there is in fact a very small current in the vehicles interior lighting system. You're therefore wrong to assume that in all cases the LED's will completely turn off after 30 minutes to an hour.

If you say so.

 

"You're therefore wrong to assume that in all cases the LED's will completely turn off after 30 minutes to an hour."

 

Were I to have had said that.

Edited 6 December, 20214 yr by J.R.