hi there, just got an audi 80 think it's a good car but MOT man will have his say in the morning, I have done a pre MOT test today but found a fault but not...

the onboard computer that displays yellow and red icon's depends on the fault
the light is displayed yellow as brake light fail however both lights work ok
I have read through the fourm to find nothing really, any one able to help me ?
any way I can remove the bulb check from the system ?

does it matter what type/ make/ wattage the bulb is ? (a dual 21w 5w 12v tail light bulb)