On an 'all-in-one' headlamp (side, dip, main), what does the fifth wire do?

I get the side, dip, main and earth wires, but that leaves one spare... does the 'pass' (flash) function have it's own circuit?

side & earth

Dip/Main & earth

Maybe??

Cheers Richard, so you're suggesting that the side bulb may not share it's earth with the dip / main bulb and has it's own?

Methinks I will have to have a lookie inside the bowl!

It might be so that you can wire it up like the Sierra (have a look in the Haynes manual if you have one) as the RH headlamp has 5 wires, although the LH one has 4. From memory on my last car, it was all to do with the dip/main beam switch.

dominatore definitely have 2 separate sidelamp wires as the sidelamp holder isn't earthed to the body of the lamp

Cheers muchly!

You are most welcome my friend.

Cheers

R