tach going crazy

[SHO_Stop'r]

I put new ends on the battery cables and now the tach jumps all the wya past 8 and is pointing straigh down.. It will not move back.. anyone know why i thought it was a ground but the lil blakc wire on the neg termail is touchign the ground so idk...

 

[Slo-Sho]

Redline any gear of your choice, the tach needle should catch itself when you get near redline. That, or you could take the instrument cluster apart.