Have 03 Super 9 LC and tach doesn't work. It's getting power and needle moves around some, but is erratic. Temp high warning light randomly lights up and goes out, so that's an issue with this instrument too. I am not smart enough to trouble shoot mine.
I think maybe just a bad connection/ short somewhere. I plan to check wiring connections next time I have plastic off. I would buy a new instrument, but don't want to install new one, only to have it do the same thing because the problem is somewhere between the sending impulse and the tach.
Have 05 Super 9 LC and tach works great. Cheers