I own a 2002 600 f4i. when i turn the ignition on, the tach lights up and does the start up cycle (needle goes to max then back to minimum) but when I crank it up, I get no reading for rpm's. The temperature gauge is also on the unit. Neither give me a reading. Any ideas of what could be wrong? I'm thinking that is the wires going to the coils which from what I understand send both readings to it. Maybe they have a problem along the way. Fuse is fine. Like I said, Its getting power, just no reading. Suggestions appreciated.

 

There's all sort of connections associated with that gauge. My best advise would be to get a multi-meter and download a copy of the Service Manual: LINK. It contains highly detailed troubleshooting instructions.
BTW ~ Welcome to CBRF & Good Luck