The outside helm station has needed attention since I bought the boat. The grab rail at the top was loose, The gauges for oil pressure and temperature did not work, There was an unmarked switch that seemed to do nothing, and the tachometer was obviously incorrect. The compass light did not work. It turns out that the oil pressure and water temp gauges, which seemed new, were connected only to power for the light within the gauge, not to the oil pressure or water temp sensors.
The wiring to the instruments was in bad shape for a few inches nearest the instruments but not so bad if you cut off a few inches and extend the wiring from the good part, which was done. Cleaning corrosion from the leads got the tach to show a more accurate reading.
The Cole Hersee warning light and buzzer unit did not work and a replacement was ordered.