I'VE installed a universal fuel sending unit with 0/90ohms and connected it to my factory fuel gauge in a 72 GMC truck,but when I turn the ign on the needle goes past full.I have checked the ground and its good and the gauge is good,so could it be I wired it wrong also should there be a fuse on the POWER side to the gauge. PLEASE HELP

Even though it may be universal, it may have different resistance and the gauge is incompatible.

YES!! everything should be fused. You can get away w/ anything over a 1 amp but no bigger than 5 amp. Fuse it BEFORE any testing! 72 Chevy should have a 0-90 sending unit, they started using them I think in 1965. If your needle pegs full look for a open (break) in the wire going from the gauge to the sending unit. Easiest way to check the wire is pull the sending unit wire & short it to ground, the gauge should read empty. If it doesn't check the wire. If it does, it's not the wire or gauge, take a closer look @ your sending unit & make double sure your ground is actually ground.

Sorry I think I misread the question, if the wire you are asking about to be fused is the wire going from the gauge to the sending unit then no, it is already fused from the factory. If it is from the fuse block to the POWER side of the gauge then YES fuse it.