Replaced NSS switch/wiring.ballest resister.voltage regulater.alternator now what???

I spinned the cable and the speedo moved but never got passed 40. Since it actually moved the speedo Im guessing that it should work. Made sure to put it back on pretty tight and than took it for a drive. Still not working so I just been driving around with someone else's arm under the dash moving it around trying to find that sweet spot. I noticed also that if I turn the lights on and off over and over its moves the speedo up higher and higher but that probably doesn't mean anything.

Thats just wierd ! The lights shouldn't have anything to do with the speedo cable unless your electrical is grounding through that cable. Good luck