I was having issues with my headlights where they would only turn on if I played with the knob and moved it back and forth in small increments. I took apart the switch and cleaned up the corrosion. One of my springs with the plastic tips that push the rockers looks melted or worn.  I am assuming this is no longer a part I can get.  Do I need the plastic piece on top of the spring or can I use the spring without it?  Is there anything I can swap the plastic piece with that could work as a fix?