My First Problem!! Number Plate Lights Stopped Working

[RicJames]

Can anyone offer any help here; my number plate lights have stopped working completely. I had LED bulbs fitted and these threw up errors but still always lit and worked but noticed last night they weren't working and so, thinking it was the LED's that had gone, I switched them back to the original filament bulbs this evening however they still refuse to light up.

I've checked all the fuses and cannot see any that have blown and all of the other lights on the car work (sidelights, fog lights, DRL's, etc) and tried several bulbs to remove the chance of a dodgy filament bulb.

Its obviously quite annoying and I'd like to be able to have a go at sorting it myself before I resort taking it to a garage.

Any help/advice would be much appreciated!!

 

[RicJames]

I've now taken this to our mechanic at work, and the voltmeter is showing a 0.67V in both lights, so I'm oping this means that all connections are still good.

Will it require plugging into VCDS and have the fault code reset? Our mechanic thinks that might sort it but he normally works with 32+ Tonne trucks and excavators, cars aren't his speciality.

 

[mike0105]

I'm not an expert on this as my problems were resolved by replacing the leds. A scan might help figure it out but the lights should still work even with a fault. Have you ruled out dodgy connections in the bulb holder?

 

[RicJames]

I must be honest, we didn't check the voltage of the actual bulb holder, but it fits very tightly and the connectors appear to line up/meet properly.

And I was hoping that replacing the bulbs with the standard ones should remove any potential issues with the LED's, but the warning hasn't cleared and they've not come back on.

 

[Quadrablast]

I must be honest, we didn't check the voltage of the actual bulb holder, but it fits very tightly and the connectors appear to line up/meet properly.

And I was hoping that replacing the bulbs with the standard ones should remove any potential issues with the LED's, but the warning hasn't cleared and they've not come back on.

A co-worker of mine had the same problem on his audi A3.
According to Audi, the canbus-system switches of the power to the bulb after a while if its broken. He took it in for a reset and then it worked. At least Thats what he told me.

 

[RicJames]

A co-worker of mine had the same problem on his audi A3.
According to Audi, the canbus-system switches of the power to the bulb after a while if its broken. He took it in for a reset and then it worked. At least Thats what he told me.

Thanks for that, it's at the garage round the corner from me and hopefully he'll get chance today to plug it in and reset it, obviously it would be good to have my number plate lit again for the miles that I do!

 

[Daniel M]

You can get units off eBay that have resistors in. Stops any issues with a the LEDs.

 

[mike0105]

I think the facelift leon is really sensitive to errors though. Would it be an idea to buy the oem audi units?

 

[RicJames]

Thanks for the help guys, took it to the local garage and they plugged it in and had to reset it, as it had registered a major fault. Apparently minor lights, like number plate and sidelights don't have a fuse and run straight from the cars CPU, and so if a fault is detected it completely shuts down, and it then required VCDS to tell the car everything is ok before it will run the circuit again. Normally a bulb going would register a minor fault and so the car would just try again when it's next switched on hoping you'd have changed the bulb by then, but a major fault is something like a short and and so it shuts down to protect the CPU. The garage thinks the LED's will have shorted and the car went into self-defence and cut the power.

Sorry it's so much to read but I wanted to write it out then if anyone else has this issue they can hopefully find this as I couldn't see anything similar to this problem on here before I started this thread.

 

[mike0105]

That is really useful to know, thanks for taking to time to add that. That might explain why LEDs cause so much bother in the longer run.

 

[Daniel M]

Yeah Mike the facelift seems to be more prone to faults with LEDs than the pre facelifts.

 

[RicJames]

Be careful with LED number plate bulbs!! I had an issue with mine, hopefully the quote of my post will work...

Thanks for the help guys, took it to the local garage and they plugged it in and had to reset it, as it had registered a major fault. Apparently minor lights, like number plate and sidelights don't have a fuse and run straight from the cars CPU, and so if a fault is detected it completely shuts down, and it then required VCDS to tell the car everything is ok before it will run the circuit again. Normally a bulb going would register a minor fault and so the car would just try again when it's next switched on hoping you'd have changed the bulb by then, but a major fault is something like a short and and so it shuts down to protect the CPU. The garage thinks the LED's will have shorted and the car went into self-defence and cut the power.

Sorry it's so much to read but I wanted to write it out then if anyone else has this issue they can hopefully find this as I couldn't see anything similar to this problem on here before I started this thread.

Edit: Cost me about £100 in the end for all the diagnostic checks, etc!