Random wire :s

Been plugging my new engine in and all seems to be going well, but theres a couple random wires that im really stumped on
The one that is making me worry is coming from just above the oil filter, its just a single red wire thats been cut about a metre or so long... wtf is it for and do i need it?

The one that is making me worry is coming from just above the oil filter, its just a single red wire thats been cut about a metre or so long... wtf is it for and do i need it?

