Tachometer Question

Do you have the tach sending unit under the kick panel and the original wiring harness?? There are 4 wires on the sending unit that loop the tach to the 12V+, ground, coil and tach. The most likely cause of a non-working tach is the old electronics. Your best bet is to buy the new circuit board from Real Time Engineering for $79.00 and get rid of all of the old electronics. I am in the process of doing that operation right now and the new circuit board fits right inside the factory "sardine can" and wires right in easy peasy. The factory wiring harness is a big help too for plug and play installation. Plus, the new circuit board is adjustable for idle and 2000rpm so dialing in the tach is also an easy task. It comes with easy to read complete directions for every aspect of installation, adjustment and troubleshooting. It also has a section that details how to test the tach itself to determine if the electronic part of the tach itself is still good. I highly recommend it, it's worth the $79.00. Good luck with your installation, Geof