Do you have the rod type control or the cable typeIJ I think with the rod type control you need to have an extra part in the wiring harnass that stops the jumping. It is listed in the combine update book that is put out every year.
Is this is different header than last YearIJ The pot is different for 21xx series heads. You need a black pot. the clear ones do not work properly with the 16xx combines. Jack
