Gauge. Not working

[newinlet]

My port water gauge is pegged in the cold position and my volts is pegged to the high side with key on engine running
Or the key off also. Any thought where to start. 1978 37c. Bridge controls only
Thanks

 

[Nonchalant1]

My port water gauge is pegged in the cold position and my volts is pegged to the high side with key on engine running
Or the key off also. Any thought where to start. 1978 37c. Bridge controls only
Thanks

If the lower helm gauges are reading correct, it's either a bad gauge or bad connections. I'd try cleaning the power and ground the connections at gauge first, because flybridge gauges are open to more moisture than lower helm usually and can get corroded. If that checks out, check continuity for both power and ground between the lower helm gauges and the bridge gauges, as the std. Hatt wiring had the bridge gauge on a wire straight from the lower helm gauge. If wiring is all OK, try swapping the lower and bridge gauge and if the problem follows the gauge, it's a bad gauge.

 

[Tinknocker]

I always check the ground first. That and corrosion are usually the culprets on Low Voltage.
Good info from the first poster.