Thoughts on this Gauge Issue

If you disconnect the fuel sender wire on the tank and measure from that point(on the wire side) to chassis
ground should read 5v this will check status of regulator, same on coolant temp sender. I would use individual
regulators for temp, oil, and fuel Radio Shack 7805 rated I think at 1amp, they are only about 2 bucks, possibly mount them remotely off the circuit board to be changed easily? I have used them many times integrated into the circuit board seem very reliable.