Chartplotter · GPS · Lights · Bilge Pump · Livewell Pump · Gauges · Batteries · Charging
Nine out of ten marine electrical faults are not the part that died. They are a corroded connection, a tired ground, a fuse that passes a meter and fails under load. Marine electrical is what we do most. Here is how a fault is actually found, what you can check safely, and where to go for your symptom.
Corrosion is the root of almost everything. Salt and moisture wick into terminals and under insulation, resistance builds, and a circuit that reads 12 volts on a meter with nothing on it cannot carry the current to light a lamp or spin a pump. Connections fail long before components do, which is why the part that gets replaced first is so often the wrong one.
Household and automotive wire does not belong on a boat. Solid-core wire breaks from vibration; bare copper turns green under the insulation and the corrosion creeps along the strands; wire nuts, tape and push-in connectors hold water. Marine work is tinned, fine-stranded copper with adhesive-lined heat-shrink terminals at every joint, and nothing else.
In Southwest Florida the corrosion never gets a dry season: salt air year-round, sealed consoles that bake, a long wet summer, and boats that live on lifts and at docks between trips. The same green terminal shows up on every second boat we open.
The order matters. Skip a step and you replace parts until something works.
Each page says what it usually is, what you can check safely, and when to stop and call.
| System | First suspects | Parts commonly replaced |
|---|---|---|
| Chartplotter / GPS / sounder | Inline fuse and holder, low voltage, corroded power plug, shorted peripheral, NMEA 2000 power | Fuse holder, power cable, battery terminals, network tee or terminator |
| Lights | Corroded socket, bad ground, blown fuse, failed switch, LED polarity | Sockets or fixtures, switches, fuse holders, tinned wire sections |
| Bilge pump | Auto-circuit fuse, stuck float, corroded wiring, burned pump, check valve | Float switch, pump, fuse holder, check valve, hose and clamps |
| Livewell / washdown pump | Airlock, clogged intake, worn impeller, low voltage, switch | Pump cartridge, pump, strainer, hose, switch |
| Gauges | Ground, ignition feed, sender, harness plug, network | Ground strap, sender, ignition switch, harness pins, gauge |
| Charging / batteries | Terminals and grounds, battery age, switch, stator, regulator, isolator or ACR, parasitic draw | Battery, cable ends, battery switch, rectifier-regulator, stator, ACR |
Every one of these gets the same order: voltage at the device, fuse under load, grounds, connectors, peripherals, then the component.
Never put in a bigger fuse, and never work on wiring with the battery connected. A fuse that keeps blowing is protecting undersized wire from a short; a bigger fuse lets the wire heat up instead. And battery gas, fuel vapor in a bilge and a dropped wrench across a terminal are how a dead light becomes a fire. Turn the battery switch off, or the negative cable off, before touching anything.
Why does my boat's electrical stuff keep failing?
Corrosion at connections. Salt and moisture build resistance in terminals, grounds and splices, and the symptom shows up at whatever device is on that circuit. Fix the connection and the device usually comes back.
Why does the chartplotter turn off when I start the engine or hit the throttle?
Cranking or a loaded circuit drops the voltage below the unit's minimum, about 12 volts on most displays. A weak battery, a corroded terminal or a fatigued fuse holder is the usual cause, not the display.
Why do the gauges all go dead at once?
They share a power feed or a ground. A single corroded plug or ground strap takes out the whole cluster; the gauges themselves are rarely the problem.
Why is my bilge pump draining the battery?
An automatic pump cycling on a stuck float, a shorted pump, or a float switch wired straight to the battery and never resting. It is the most common parasitic draw we find.
Can you fix it at the dock?
Almost always. Fuses, connections, grounds, switches, pumps, floats, senders and most wiring repairs are done where the boat sits. Only a major rewire needs the boat pulled.
What does the visit cost?
A $250 diagnostic visit in regular hours, $295 after hours, Sundays and holidays. We find the actual fault and quote any part before it is replaced. A fuse, a connection or a float switch is usually done on the same visit.
Do you install electronics too?
Yes: chartplotters, fish finders, radios, lights, pumps, switch panels, batteries and charging systems, wired to marine standard, tinned and heat-shrunk, with the circuit protected correctly.
We come to the boat with the meter, the test loads and a stock of marine fuses, terminals, tinned wire and the common pumps, floats and switches. The fault is traced in the order above and shown to you at the boat. Anything beyond a quick fix is quoted in writing before the part is ordered, and the connection that caused it is repaired to marine standard so it does not come back.
Regular hours (6am–4pm): a $250 diagnostic visit. We come to the boat, find the actual cause, and quote parts and labor before any work starts. After hours, Sundays and holidays: a $295 call-out. Quick fixes — a fuse, a connection, a pump cartridge — are usually done on the same visit. Parts, labor and sales tax always show as separate lines on the invoice.
Whole boat, not one fault? A harness corroded end to end, a panel falling apart, electronics from three different decades — that is a project, planned with you and done in the shop: repower, rewiring & rigging.
Engine due for its service too? See the Premium Full Service, parts included and one price per engine.
Dock, lift, marina, driveway or storage lot — we come to the boat across Southwest Florida:
Text us what is not working, the year and make of the boat, and where it sits. You get a straight answer about what it probably is, and a day we can be at the boat.
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Problem pages: GPS not working · Lights not working · Bilge pump · Livewell pump · Gauges · Battery keeps dying · Trim not working · Boat won't start