Keep up the good work!
My .02; I've had 2 bowlers that had wiring shorting out where the larger harnesses were clamped down (I guess years of vibration had thinned the insulation a little bit) - you may want to check that out if you still have issues.
Also, be sure all the switches have the fishpaper insulator intact. Funky things can happen when fishpaper is broken or missing....