Have a 98 A4 1.8T . Shows w5w light but it's not. Map light is bayonnet type / push in and turn - small . Unable to find any info in owners manual or repair maunual for these two bulbs (sits either side of festoon light under rear view mirror) . Anyone out there know what the damn things are??

 

They are BA9 - bayonet base 9mm. Are you looking to go LED or just the regular replacement?

 

LED if possible

 

Be careful if you find a polarized LED. DDM Tuning sells a nice BA9 LED bulb, but its polarity is opposite from how our cars are wired. I ended up taking the DDM BA9 bulb apart and switching the polarity, which wasn't an easy task.

Super Bright LEDs makes a BA9 bulb that is non-polarized, but the output of that bulb is NOTHING close to the DDM bulb.

 

You know I have just tried to install LEDs in the rear light housing unsuccessfully I wonder if the polartity is reversed there. I'll keep that in mind. All of my interior LEDs went in fime on my Porsche but polarity can easily be reversed on all the lights . Not sure with the Audi but will try. Thx Steve