I have a 2004 Hyundai Santa Fe, the RPM gauge just sits at Zero, any tips on how to fix this?

It could have disconnected at either end, could be a broken wire or it could be a bad sending sensor.

which end? do you have a link to a diagram that I could be able to see?

Sorry I have no diagrams. As I said at EITHER end. It doesn't matter if a car has an electrical speedo/rpm gauge or a mechanical one. In both cases there are 2 ends the electrical will have a connector that clpis onto the back of the instrument panel and the other clips somewhere on the trans-axle or tranny. A mechanical would have 2 mechanical type ends, one would clip or thread into the back of the instrument panel and the other end would bolt, clamp or screw into the the trans-axle or tranny. Have you checked the car for any stored trouble codes? Some can be stored in memory but not trigger the check engine light, and if there are any in memory it could possibly make your problem easier to fix. You can try googling for a diagram.

thanks i will take it to autozone to read the codes, because the check engine light is on

Did the problem ever get resolved? Have the same problem with mine.