Picked up a new TTT from eBay, looks great, but when I installed it nothing, no clock, no tach. Checked power to wiring, all is good. How can you bench test the tach? Took it out of cluster and just ran a 12v lead to the clock and grounded it, still nothing. Am I wrong or is this bad. Checked the tach this way, ran leads to my coil, positive battery and grounded it, nothing also. Was this correct? Any advice before I contact seller. He claims all are checked before shipping