Possible bad Thruster switch?

scottgrierc3

New member
Joined
Feb 14, 2025
Messages
4
Fluid Motion Model
R-23 (Outboard)
Hull Identification Number
FMLT2347K718
Switch won't light up on dash, or operate thruster. There is power to both sides of the AN fuse............... and the Red inline switch.........but switch won't turn on. Is there another fuse?
 
Switch won't light up on dash, or operate thruster. There is power to both sides of the AN fuse............... and the Red inline switch.........but switch won't turn on. Is there another fuse?

Pull the switch out. Maybe the connectors on the underneath have wiggled loose.

Happened to me. One of the least expensive and quick repairs.
 
Yes there is another fuse. There is a 2amp control power fuse at the thruster itself, it is a glass fuse approx. 1/4 x 3/4". We recently had the exact same thing happen and traced to a failure at the fuse... but it wasn't the fuse, it was the connectors to the fuse. The area is prone to moisture, and there is no dielectric grease installed to prevent corrosion at the fuse from the factory. For us (hopefully the same quick fix for you), I just took my wife's nail file (what was quick to grab) and cleaned both sides of the fuse and brass contacts to the fuse where there was built up corrosion. On my list of items to do tomorrow I'm replacing the glass fuse holder with a 'standard blade' type that is used throughout the boat so it's more or less universal throughout the boat, and the fuse holder will be weatherproof and contacts filled with dielectric grease.
 
Last edited:
Yes there is another fuse. There is a 2amp control power fuse at the thruster itself, it is a glass fuse approx. 1/4 x 3/4". We recently had the exact same thing happen and traced to a failure at the fuse... but it wasn't the fuse, it was the connectors to the fuse. The area is prone to moisture, and there is no dielectric grease installed to prevent corrosion at the fuse from the factory. For us (hopefully the same quick fix for you), I just took my wife's nail file (what was quick to grab) and cleaned both sides of the fuse and brass contacts to the fuse where there was built up corrosion. On my list of items to do tomorrow I'm replacing the glass fuse holder with a 'standard blade' type that is used throughout the boat so it's more or less universal throughout the boat, and the fuse holder will be weatherproof and contacts filled with dielectric grease.
Hello Island Hopper and thank you for this bit of info. Is the fuse in the anchor locker, or in the V-Berth down in the hull? I don't have power to the switch light either at the joystick.
 
The bow thruster control power fuse is in the V-berth, under the most forward cushions there is a hatch that provides access to the thruster. ( on the R-27 )
 
The bow thruster control power fuse is in the V-berth, under the most forward cushions there is a hatch that provides access to the thruster. ( on the R-27 )
If the fuse blows, you may have something fouled up in the thruster itself. You don't want to shear the pin...
 
This particular fuse is the "Control" wire fuse, or the control side of the circuit - not higher current motor side of operation. It separates the lower current of the thruster directional switches and coil side of the solenoids. If it blows there is a short in the wiring to the switch (highly unlikely), a shorted LED light by the panel (highly unlikely) or a shorted/high current demand in one of the solenoids that operate the higher current demand of the motor. Hope that makes sense 🙂. It's not in the Lewmar110TT Manual which is frustrating (at least the one I have). I believe I had to remove the side cover, and cut some zip ties to access it better. Mine wasn't blown, the corrosion was limiting the power to turn the LED on and pull in the solenoids.
 
Here's are some pictures of where the fuse is located.
Bow Thruster.jpg
Bow Thruster Original Fuse.jpg
 
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