Sealander,
On my 2010 R-25, there are two separate fuses/breakers controlling each bilge pump. The breaker close to the dash controls the manual operation of the pump. There is a second breaker controlling the automatic operation - that is if the pump is switched on by the float switch (or equivalent), it is controlled by a different circuit than if the pump is switched on manually from the helm.
On my Ranger (probably because of a previous owner "mod", the automatic operation is controlled by a blade-type fuse connected to the THRUSTER BATTERY. The manual operation is controlled by a breaker (and upstream fuse) connected to the house battery.
If you switch on the manual control at the helm when the automatic control in the bilge is demanding pumpout, it has the effect of connecting the house battery to the thruster battery, blowing the bilge pump fuse in the process. This is not the way Ranger designed the system, but it may - or may not - have been a previous owner mod.
In any case, the effect is the same - no more automatic bilge pump operation.
In troubleshooting this (I love boat puzzles), I found several of the fuses were corroded in their holders - as you would expect from long term connection of dissimilar metals in a marine environment.
For about $11, I purchased a collection of blade fuses from Amazon. (ATD Tools 364 120-Piece Car Fuse Assortment) and changed ALL the fuses in the battery compartment - the boat is 7 years old and they were all slightly corroded). I also replaced the bilge pump fuse that is on the automatic stern circuit with a circuit breaker from Amazon (Blue Sea Systems Push Button Reset-Only CLB Circuit Breakers with Quick Connect Terminals). This gives me an "at a glance" view of the stern automatic pump operation.
Since then, no problems.
This does not represent, in my opinion, a defect in manufacturing (see below). Fuses used in a marine environment are zinc plated to reduce corrosion - after a time the zinc goes away. The fuse holders are sealed to prevent water ingress, but humidity has a way. Check and replace your blade fuses after 5 years or so - if you see corroded fuse blades, change them all, if not, just be happy for another five years.
Below: The problems I experienced were made worse by the lack of scupper screen removal. As Andrew suggested, you should remove the scupper screens and clean/check the scuppers regularly. I didn't do this, so some water entered the engine compartment in the area of the fuses. I think this accelerated a problem I would have experienced anyway.
For $11, you can buy a lifetime of blade fuses, change them every 5 years or so, and never experience any probles.
/Stu
