Extra Servo wire?

[Click]

Hi,

Purchased a used Tamiya M03, need to change the ESC to a standard Tamiya unit (club rules!)

Everything is fine apart from one extra cable. There is a single cable coming from the existing ESC (not Tamiya) to the servo?

There is the usual 3 core cable coming from the servo to the receiver BUT there is this extra single cable from the servo to the ESC anybody know what this is for?

Depending on the answer I get is there anyway of using this cable with the standard Tamiya ESC (TEU-101BK)


Thanks in advance