I found a convenient spot in the cockpit to install three gauges so I can keep an eye on battery charging (volts), engine oil (pressure) and cooling (water temperature). It’s on the starboard cockpit coaming on the inside wall between the propane locker and the cockpit where the builder had installed the remote windlass rocker switch. I relocated the switch nearer to the top of this coaming and cut a hole for the stainless bezel and the eight small bolts. I had be careful not to cut through to the propane locker. Once the bezel and gauges were in place, I ran the wiring down to the engine compartment under the companionway.
The original oil pressure sensor is fitted to the engine near the oil filter. I replaced the sensor with a fitting and high-pressure hydraulic hose that leads to a tee fitting. On one side of the tee, I attached the original pressure sensor which feeds the idiot light in the Yanmar engine panel. On the other side of the tee, I fitted a pressure sensor that feeds the oil pressure gauge in my new panel.
I found a place to install the water temperature sensor in the water loop that runs through the hot water heater. This location is a compromise, as I didn’t want to remove any plugs in the engine water loop. The compromise is that the temperature is being read a bit downstream from the thermostat and no water passes through this loop until the thermostat is open (i.e., the engine is already hot).
Here’s a wiring schematic.
I had a stainless bezel made by a local shop (Orleans, Ontario). Here’s the template (scroll down once you click the link).