2007 Dyna (FXDB) rear light Query.

In a bid to replace the sit-up-and-beg registration plate on my bike I have grafted on the tail section from a 2019 FXDB where the plate sits below the rear light, rather than above it.

I now need to piggy back the original running light to power the number plate light on the new unit.

The old light is combined rear light/brake light and has three wires to it, namely: black - blue - red/yellow and I need to know which is the rear light, as I'm assuming the ground is black.

I have the correct Clymer manual for the bike which under Wiring Diagram helpfully states See CD; I have the CD but no means of playing it

Equally helpfully, the new light has two black wires only !

Can anyone say with certainty Blue or Red/Yellow ?

See that multi-meter in your tool kit?

Doris said:

See that multi-meter in your tool kit?

Click to expand...

Yes, the practically unused one you mean ?

Actually that's not a bad shout, from you !

oblertone said:

Yes, the practically unused one you mean ?

Actually that's not a bad shout, from you !

Click to expand...

That's the one, right next to the unused test light.

A quick bit of research on the web...

Black = ground
Blue = rear light
Red/yellow = brake light

Thank you, your PoG (Powers of Google) is stronger than mine

Actually, Doris's suggestion wasn't too bad despite him being a cock; so I was able to confirm blue = light with it. Another clue being there are two red/yellow feeds from the rear loom which would make sense for front & rear brake light switches.