I took the car out for a spin on Saturday and returning home I stopped for some petrol.  Getting back in the car I turned the headlights on and a warning message came up on the dash "Check Number Plate Light".  Jumped out had a look and sure enough the NS number plate bulb was out.

Got home and was fannying about in the garage before putting the car away so the car must have been stood for no more than 10mins.  Got back in the car, the headlights were already ON from coming home... waiting to see if the warning message came up, nothing.  Got back out check the bulb and it is now working.  Must be a loose/dirty connection.

Later on I had to go out and pick up SWMBO on with the lights and no warning for about 10mins and then up it popped bulb out.  About 3mins after that the dash backlighting then went out.  A min or two later on it popped again.   This occured a number of times on the return journey.

Returned home and now with a bit of time on my hands got the bulb out to look and see if the connectors were clean and good fit, which they were.  At this time the bulb was not working, and no visible break in the bulb element.

To check and make sure the bulb was at fault, I swaped the number plate bulbs around - the working bulb in the non working posistion.  Sure enough this confirmed that the bulb was at fault as the faulty bulb (now in the OS location) did not work.

I've got in the car this morning and the offending bulb still in its reversed location is working again! 

I'm going to pick up a new bulb later on, but what worries me more is that its knocking out the dash backlighting (the Dimmer setting is on Max).  The two are clearly connected as I've not noticed the backlight dissapearing before the bulb has played up


I take it this isnt usual behaviour?!

Bulbs can misbehave for  any number of reasons and changing it will probably fix it.

Yes granted, especially the (bayonet?) type found in the number plate lights.  I have had bad experiences of these in past.

What time of day was it because it sounds like it may have been dusk and the ambient light sensor will put out the dash lights if it thinks it too bright to have them on

It was on pretty much all day- we had the very overcast grey mirk all day.  Being that the car is grey and the drives included trips along M5/ M4 etc I kept the headlights on all the time.

I didnt think there was a sensor for the dash light? 

I thought the sensor was something as simple as my left thumb and forefinger turning the headlights on to get the dash backlighting on... TBH though I havnt driven the car as much with the headlights as much as I did at the weekend so I dont know if I have a sensor or not!

I dont have HID's BTW.

Just stick some tape over the sensor
Its the dome shaped thing in the middle of the dash close to the windscreen.

Thanks for the info, I just assumed that the Auto On/Off function would be associated to the HID option and noticing the on/off is just coincidence to the fact that the bulb blew and sent (what i thought) the dash into assumed "melt down"  

As mentioned above though, I do find the dials hard to read at the best of times, especially coming from a car where the speedo was a centrally dash mounted translucent digital item, with automatically adjusted dash lighting!   I tend to find myself staring and squinting at the A500 speedo especially with the number of cameras around my way....  

I dont see the point of turning the backlighting off either, especially as if anything it needs it switched on!  Perhaps I could make a small unubtrusive cap to go over the sensor.  I take it though it only turns OFF the dash backlighting when the headlights are ON?