1.0a Wiring Harness Issues

I have a 1.0a flashed with repetier. My main wiring harness going to the PCB in the hot end failed sometime ago. I kludged it back together by direct soldering a new harness to the back side of the connector and splicing etc. That fix has since failed again.
one of two things I need to know. Can i bypass the PCB and just direct connect my Thermistor and the 5v fan, since I don't need the filament sensor to work. Or the two red wires I need to know if they are interchangeable or how to test which is which.