Wiring diagram for a 1978 22 Ft Aquasport Family Fisherman

[pi4dom]

Does anybody know where I can get a wiring diagram for a 1978 22 Ft Aquasport Family Fisherman?

I bought this boat a few months ago and the cockpit lights don't work. And none of the gauges are working either.

I found a missing fuse so this may be part of the problem.

I also found another fuse so I removed the fuse thinking it will be the same fuse that is missing.

The fuse is 6 Amp at 250 Volts which seems odd to me. Why would there be a 250 Volt fuse if the battery is only 12 Volt? Then again the fuse is linked to a cigarette lighter which could be used for an DC/AC inverter.

If anyone can help it would be deeply appreciated.

Thanks

[mshugg]

It’s not unusual to see some fuses marked for a higher voltage, especially the glass ones.  The important thing is the amp measurement. 

Its highly unlikely that you’ll find a wiring diagram for a 78, and the wiring may not be original anyway.  Best bet is to trace things back with a multimeter.  Splices, connections and switches are all likely suspects, though with that vintage boat corrosion can creep up the wires too.

[RickK]

I agree with mshugg.
If you think about it there are only a few circuits in the boat that are not in the engine harness. Most non-engine circuits will originate in the console or behind the helm. Usually you'll find a + bus bar and a - buss bar in the the console or behind the helm.  The + bus bar will be fused near the battery.
I'll start a list:
Nav lights - one circuit to the front, one to the rear. Usually on the same switch - fused.
All around light - one circuit - switched - fused.
Bilge pump (my old 170 didn't have one from the factory) Usually attached directly to the battery but has control wires (float switch remain back where the pump is and to battery) to the helm.
Find the connection from the battery to the helm and there should be a 30+ A fuse on the main line to the helm.
Those are the standard non-engine related circuits.

Depending on what the previous owner added: The + bus bar and a - buss bar in the the console or behind the helm are where these are powered.
Could be a Fish finder (FF)/Depth finder or combo chart plotter/gps/ff unit that has a either an integrated antenna or an external one, and could have a transducer on the back of the boat for the FF.
Could be a stereo system with speakers that have been run.
Could be a search light.
Could be a windlass.
Could be LED lights (or old incandescents) for night lighting
Could be bait well wiring.
So there is possibly a lot of added circuits connected to the bus bars. And all the lighting circuits for the gauges are connected to the ignition/- bar.

Have to tackle the circuits one at a time with a meter. Mark the circuit wires as you figure them out.