Help?, Oil Sending Unit Options

[6G96GT]

I posted an initial thread for this topic but I can't find it so here goes...I was running a mech. oil pressure gauge along with the factory oil sending unit via a T connection into the head. I wanted to be double safe on my Oil Press. Anyway I went to change the oil sending unit and when I released it the cap that has the wire into it coming from the wire harness snapped and so I am wondering is this going to be a costly wireharness job from Toyota to fix or can I just go to a junkyard and snip one off another Celica and then splice it into my original broken wire??