I have the R580 (7443) W21/5W Gen2 CANBUS 27* SMD 5050 LED bulbs fitted as DLRs and the passenger side bulb lights up perfectly when my lights are in the 'off' position, but when I click onto side lights it goes off completely (whereas the drivers side dims to the lower brightness as it should) and the passenger side bulb stays off if I click onto full dipped beam (whereas the drivers side one stays lit as it should).

 

Do I have a dodgy bulb - is it possible for the 21W brighter setting to be OK and the 5W setting be broken?

Swap over the bulbs to iliminate the bulb!

Did the "dodgy" lamp do this from new...or has it just started doing it? If the former, then do as suggested above. I think you may have a faulty unit...exactly the same happened to me - one behaved perfectly, the other as you have described. I phone HIDS direct, described the problem and they replaced without question.

...and should have said that both have been fine for the last five months!

Just started doing it, bulb is past the 12 month warranty.

Guess it's time to buy a new bulb - and yet I bought LEDs for their long life - oh, the irony!

They're all a waste of time in my opinion. I've tried so many and they all fail so quick. Keep it standard and save some money.

They're all a waste of time in my opinion. I've tried so many and they all fail so quick. Keep it standard and save some money.

Nope :p the led's in question are the one's I have, have lasted me for months so far and should do for the cost, I think it's just the cheapies that are dodgy