The question I would ask is why would you need to rewire if the gauges previously worked and you didn't change those connections? I think you are on the right track with the PCB or the ground as those are more likely to impact all the gauges.
1968 400 Coupe, verdoro green, black vinyl top, auto 1969 GTO Judge coupe, Carousel Red, manual 1971 Trans Am, cameo white, auto 1970 Buick Skylark Custom Convertible 350-4(driver), Fire Red, white top, auto 1972 Buick GS Stage 1, Royal Blue, black vinyl top, auto
