Taillight Wiring

[Ukemax]

I'm replacing my taillight and there is another yellow plug that wasn't attached.

Silly question. But what is it for ?

Thanks in advance

 

[maleko89]

The wires going to rear fender are turn signals, tail light, brake light and ground.

 

[Zeus36]

I'm replacing my taillight and there is another yellow plug that wasn't attached.

Silly question. But what is it for ?

Thanks in advance

Pull back the sheath and see what the wire color(s) is/are.

Looks like it might be this: