I have just replaced the cable from the wind instrument to the head
to solve this problem on my boat. The solution is via incremental exclusion as I'm unconvinced by the utility of the voltage parameters in genuinely sorting out cable versus masthead faults.
As it is easiest to check the connections at the mast
step junction box and to the back of the head
, I'd do that first. Then, suggest you connect a second anemometer and cable to the head and see if it works. If obtaining one is problematic, I'd suggest you simply purchase
the cable at about $55-75, make a trip to the mast
head, unplug your anemometer, bring it down and plug
it in using the faultless new cable connected directly to the head. Thus, for less than 30 minutes of technician labour costs, you'll know if its the cable (in which case you've wasted nothing becuase us need it), or otherwise. My bet is it will be in the cable or in the connections. Differentiating between the anemometer and the head will likley require a tech who has a spare to substitute.