Today I was checking on what options were activated on my mk3 and I noticed that the bulb failure feature was not active, so I enabled it and I then got an message telling me to check my number plate lights bulbs and I have 2 bulbs working OK despite the warning flag. I expect that these bulb detectors work by measuring the current a circuit is drawing, so if a bulb is blown, the circuit will not be drawing its normal current thus flagging it up as a bulb failure? So with this in mind, if someone has fitted LEDs in the number plate holders, the circuit would be drawing less power and hence the flagged warning? My owners manual makes no mention of what bulbs should be used and where other then the main ones, or how to access the number plate lights. How can I find out bulbs are fitted, how do I gain access to them and what bulbs should be fitted?

1 hour ago, Graham Butcher said:

Today I was checking on what options were activated on my mk3 and I noticed that the bulb failure feature was not active, so I enabled it and I then got an message telling me to check my number plate lights bulbs and I have 2 bulbs working OK despite the warning flag. I expect that these bulb detectors work by measuring the current a circuit is drawing, so if a bulb is blown, the circuit will not be drawing its normal current thus flagging it up as a bulb failure? So with this in mind, if someone has fitted LEDs in the number plate holders, the circuit would be drawing less power and hence the flagged warning? My owners manual makes no mention of what bulbs should be used and where other then the main ones, or how to access the number plate lights. How can I find out bulbs are fitted, how do I gain access to them and what bulbs should be fitted?

The number plate bulbs are LED as standard and non replaceable.

 

Could be both of yours failed and someone replaced them with non standard but unlikely.

 

Potentially the poverty spec ones arnt LED as standard and would then have the bulb warning enabled, not sure though as I thought they were all LED

 

Was this option you found in the headunit settings or vcds/etc? If the former then something is wrong

Edited 15 June, 20232 yr by Danoid

34 minutes ago, Danoid said:

The number plate bulbs are LED as standard and non replaceable.

 

Could be both of yours failed and someone replaced them with non standard but unlikely.

 

Potentially the poverty spec ones arnt LED as standard and would then have the bulb warning enabled, not sure though as I thought they were all LED

 

Was this option you found in the headunit settings or vcds/etc? If the former then something is wrong

Yes, it was an option I found when playing about with my old Carista OBD11 unit. I do have a VCDS as well but I'm still learning how to use that correctly so I didn't use that for checking the options. IIRC the number plate bulb warning was on its own as a feature as were all the other light monitoring options, so I could always just deselect that option Until I get more  time to check out the bulbs situation. I seem to recall that when I was checking though cars previous MOT history, it did fail one because it had no working number plates lights, so you may ne correct in your assumption, I'm still working my through the fine tuning to get this car how I like it, its just 2 weeks since I collected it.

 

I also have a few other fault codes that I need to try and resolve, but they don't thrown up any warnings so must be just minor ones, but faults all the same and I don't knowing the car has faults so maybe I'll check them again tomorrow, do a reset and see if they come back again and post the codes.

Edited 15 June, 20232 yr by Graham Butcher

Yeah, I’d just do a reset and check it a few days later.