I have a tach for a 67 camaro and I'm trying to install it in my car. I have made the changes to the wiring harness and it is hook up correctly, but it doesn't work. I have taken my tach/dwell meter and hooked it up to the the dash harness and it works. The tach was hooked up to the coil and it didn't work. So I'm pretty sure the tach is broken. I have and HEI distributor, would that make a difference? I don't think it should. Any one know who can repair tachs?