Low voltage at breaker box

[Chrisrog]

I connected a light to the 12v accessory lead today, turned it on, and now the boat won’t start. I checked the voltage across the positive and negative terminals on the circuit breaker box, and I have 3.5v. Perhaps I fried the On / Off / Bilge switch? Any ideas how to troubleshoot this?

[MLA]

Whats the voltage at the input and output of the on/off/bilge switch? Voltage at the battery(s)?

[Chrisrog]

Thanks for the input.

Battery is 12V +/-.

into the toggle switch is 12v +/-.

out of the toggle switch is 3.4v.

I took the switch out and went to a couple of auto parts stores. No luck.

Dropped by an ACE hardware and found a match that only required me to make up a set of pigtails to be able to plug into the leads.

It all works again. I will remove the light bar that caused this issue and convert to LEDs.

[MLA]

Power the light bar with a relay wired to a more substantial power supply. trigger the relay with your existing light switch, which is supplied through the off/on/bilge switch. No additional load on the off/on/bilge switch or its factory intended circuit.

[Chrisrog]

Good idea. I hadn't thought of using a relay. I am planning to revisit the light bar when I get around to adding a second battery. This light bar has 6 halogen fixtures on it but only 2 are in working order. I was trying to fix one of the four other fixtures when this happened. I suspect I shorted out one of the fixtures internally and the circuit breaker didn't catch it. Since the fixture is old, draws a lot of current compared to newer LED fixtures, and only half works anyway, I think it's going in the trash.

Now I need to find a couple of washers for the knurled nuts on the bilge circuit breaker and master switches. The decal doesn't last long in this location if you remove either component. Even the example in the owner's manual looks bad. I'm planning to add a washer to act as a bezel and protect the edges of a new decal, if I can find one the right size.

[core-rider]

You'll need a relay circuit regardless if you use halogen or LED lighting... That's just too much load for the switching circuit to carry.

[Chrisrog]

With what I've learned over the past few days about the fragility of the master switch, all new electrical loads, including the amplifiers I haven't yet re-installed, are going on a fused distribution block powered by a new house battery. I may take a couple of the existing loads (hatch motors, nav / anchor light, stereo, etc.) and shift them over via relays as well.

My project for next winter will start with an enlarged battery box and finish up with replacing all the old, tired carpeting.