I recently wired up my instrument gauge back lights. I have a Voltage Gauge, Tachometer, Water Pressure, Fuel, and Speedometer. All gauges worked no problem at the end of last season and they are only about 1 year old. The power to the instrument gauge lights is fed from my battery to a manual on/off switch and then to the individual gauges. When I turn flip the switch, all the back lights come on except the tachometer and the water pressure gauge. My question is do I need to have the engine running to get these two lights to come on. It's still winter here so I hate to have to drag the boat out of the garage to fire it up right now. The lights feed from the switch to the voltage gauge and then to the tachometer. All the other back lights are jumped from the tachometer light ring post. It just seems odd that the others would work, but not these two.
