The J/109 Class Association Forum

While at the boat today I was surprised to find a few ground cables not connected. First, I noticed the green ground was not connected to the ProNautic charger.

Secondly, I noticed within the engine compartment another ground (black) that was disconnected. I am assuming this connects to the alternator, but I was unable to find any detailed wiring diagrams within the service manual. Curious if anyone else had a similar issue with the ProNautic boat ground. Additionally, does anyone happen to have a more detailed wiring diagram for the alternator, assuming this is where the loose engine compartment cable attaches. Pictures attached.

Matt,

The grounds should be connected. Trace the disconnected wire by the engine to verify where the other end terminates.

From the ProNautic Manual page 11:
3. Ground - This is extremely important and often overlooked. There is one common battery
ground with the positive battery connections on the ProNauticP. There is also a “Chassis Ground”.

a. Battery Negative - As shown in the diagram, this is connected to a bus bar or terminal
stud (not included) that can handle, at a minimum the amperage of the charger output
(1260 = 60 amp minimum). This conductor shall be of equal size to the DC positive conductor
chosen above. The battery negative terminals are connected to this bus bar or terminal stud.

b. Bonding Stud A.K.A Chassis Ground - This stud is connected to the boats bonding system
as well as the bus bar or terminal stud mentioned above. This conductor is permitted to be
one size smaller than the DC positive conductor chosen above; in the case of a DC to the
case fault, this conductor is critical in carrying the fault current to trip the fuse or breaker,
the AC ground CAN NOT handle high DC amperages.

Great. Thanks for the details, Bill.

I have a floating unconnected black wire near the alternator also. Like to hear what you learned.

Dan

Dan,
I was able to trace the black cable to an opening in the wiring harness (indicated in red on photo). I plan to take a longer look next week to figure out where it is ultimately coming from (in hopes to figure out where it attaches).