re there two bulbs in main beam?

[xpress]

JUst a quick one, I know you all like a quickie, especially bmc!

DOes the main beam have two bulbs and can main beam fail and dipped work in one headlight and vice versa?

It's either a bulb or the wire which looks black not copper strands to main beam, or its a connection on the main beam.

[bmcecosse]

Well there are two FILAMENTS in each headlamp bulb or sealed beam unit - and yes one can fail leaving the other working. Copper wires 'gone black' are bad news - should be cut back to clean copper and remade. Spray with WD40 to help preserve once sorted.