Ignition wiring linked to non-switched accessories?

[am_dew]

While cruising in my 1972 Delta 17' runabout last week on a lake, all of the sudden the engine suddenly stops and I also had no power to my gauges or accessories. I crawled under the dash and finally found a loose red wire which is part of the main wiring harness that leads to the back of the boat. I am not familiar with my boat's wiring so I start looking for an empty terminal that this wire may have come off of. Sure enough, I find a terminal on the ignition switch without anything on it, so I (hesitantly) hook it to this terminal, and then everything worked again. Turns out that my girlfriend had apparently stressed the main wiring harness while pulling a paddle from the side pocket enough that some bouncing around caused this wire to come off of the terminal on the ignition switch. I was surprised that a wire attached to the ignition switch would have caused accessories that do not require me to turn the ignition switch to the ACC position to fail. Is this typical of the way older boats are wired?

Needless to say I have since put my paddle in a different place and also have fixed things so that the wiring cannot get stressed like it did and get pulled off of terminals.

 

[seabob4]

Re: Ignition wiring linked to non-switched accessories?

On most boats (all that I've ever built or worked on) have the engine electricals and the boat's electricals in two separate systems, only sharing a common ground. In other words, if the positive feed to you boat's equipment fails, the engine will be fine, and visa versa. However, should the ground fail, both systems will go down.

Seeing as your boat is almost 40 years old, and God knows what's been done to it in all those years, it would be anybodies guess as to how it is wired...

 

[Silvertip]

Re: Ignition wiring linked to non-switched accessories?

Look carefully at the wires on the battery. You should find the two large cables that go to the engine. You should also find two smaller wires (typically #8 or 10 gauge). Those wires are the feed to the helm, the accessories but typically NOT the gauges since you want those to come alive when the key is in the RUN position. That red wire is +12 volt feed to the ignitiion switch via the large harness that runs between the engine and control box and onto the ignition switch. The "A" (accessory) terminal on the switch is what energizes the gauges.