Yanmar control panel dead-trouble shooting hints?

[jimbojonesbos]

Hi Everyone,
yesterday when I tried to start my 2gm20f, I got no buzzer and a dead panel, no lights no tach, nothing. The engine had been run about 4 hours prior and has about 25 hours of total runtime.

Being in a tight spot at the moment I started it with a screw driver at the starter so the issue is not mechanical and the starter gets power

and battery banks are both over 13v.


I could find no loose connections or damaged wire and I am at a loss as to where to begin diagnosing the problem.


One pertinent bit of info is that my house bank is 200ah of battleborne lithiums and I had been running with the start switch on "both" so one thing that is on my mind is that perhaps I overtaxed and cooked my "dumb" 70 amp alternator.


Can any of you offer some ideas on angles of attack before I admit defeat and hire a mechanic? Engine electrical is obviously a shortcoming in my knowledge set.

Any and all ideas are appreciated.
thanks in advance!

[Calif.Ted]

There is 20 or 30 amp (I forget which) inline fuse in the main wiring harness that supplies power to the panel. It is usually on top of the engine in the plastic loom wrapped with copious amounts of electrical tape. It's not that the fuse blows much but the holder is a poor design with crappy contacts in a place that's hot and vibrates alot.

[tkeithlu]

No need to go to the pros - a failure that massive and reliable will not be difficult to trace.

OK. An obvious place to look is whether the panel/run/start switch has failed you.

That aside, the usual approach is to start at one end with a multimeter or even just a lightbulb and alligator clips, either tracing until you find voltage, or tracing until you lose voltage. The batteries are full, so you have volts there. You might start behind your panel to see whether volts get to the switch but not beyond to the lights, etc. Trace until you find the fault. That's more reliable than looking for corrosion or loose connections. If you get a low voltage, say 5 volts when you expected 12.8, that's corrosion or a loose connection.

Then, let me recommend Charlie Wing, Boatowners Illustrated Handbook of Wiring:
https://www.amazon.com/Boatowners-Il...s%2C357&sr=1-1

or Nigel Calder's:
https://www.amazon.com/Boatowners-Me...s%2C357&sr=1-2

You don't want (I think) to be stumped by these sorts of failures. That would mean spending a lot of money on pros fixing what you can fix, or having a failure when they are not available, which is even worse.

Go for it.

[tkeithlu]

Nice call, Califorina. Prime candidate for the problem.

[jimbojonesbos]

Originally Posted by tkeithlu

No need to go to the pros - a failure that massive and reliable will not be difficult to trace.

OK. An obvious place to look is whether the panel/run/start switch has failed you.

That aside, the usual approach is to start at one end with a multimeter or even just a lightbulb and alligator clips, either tracing until you find voltage, or tracing until you lose voltage. The batteries are full, so you have volts there. You might start behind your panel to see whether volts get to the switch but not beyond to the lights, etc. Trace until you find the fault. That's more reliable than looking for corrosion or loose connections. If you get a low voltage, say 5 volts when you expected 12.8, that's corrosion or a loose connection.

Then, let me recommend Charlie Wing, Boatowners Illustrated Handbook of Wiring:
https://www.amazon.com/Boatowners-Il...s%2C357&sr=1-1

or Nigel Calder's:
https://www.amazon.com/Boatowners-Me...s%2C357&sr=1-2

You don't want (I think) to be stumped by these sorts of failures. That would mean spending a lot of money on pros fixing what you can fix, or having a failure when they are not available, which is even worse.

Go for it.

No I definitely do not want to be reliant on pros. I prefer to pay folks to do things I don't want to do (like glasswork) rather than that I can't do but I am admittedly very frustrated by a series of unrelated things breaking all at once .
Thanks for the tips and hints

[Redline452]

The 2GM20F panel on my previous boat had the "keyswitch" break at the threaded part through the panel - so I temporarily rewired to the compass light switch nearby. If you have the flat key version, it's a simple on-off switch (though one that looks as if it was designed by a diesel mechanic - very heavy contacts (in a plastic body)). The one notch in the "key" is only a spot for a ball bearing to drop in to prevent the key falling out while turned on.



Still, start looking for power at the battery then working toward the engine and panel. There are multiple connectors in the wiring harness, any one of which could be interrupting the current.

[Secondshift]

+1 for key switch. If you have an electrical contact cleaner you might try
to spray and agitate it.

I'd suggest the Clymer Manual. Much model specific info and photos.

Though it simply states, " Key Switch -Perform voltage or resistance checks ... " , for your dilemma.

https://www.amazon.com/Clymer-Yanmar.../dp/B006O1JPXM

There is a copy of the original operators manual viewable at

http://j30.us/files/yanmar-manual.pdf

Best Luck,

Please tell us what you find

[DIJ]

I think Calif-Ted has provided good advice and a place to start the investigation - the problem described is one I have experienced and the cause was poor connection on the fuse described - in my case wrapped in electrical tape behind the starter motor. Fuse was ok but the connections were corroded. It came to life and buzzer sounded as I was unwrapping the tape.

[j.g.evans]

My Yanmar wiring harness developed high resistance and could not pull in the solenoid on the starter. The panel would be dead while trying to start. I solved this problem mounting an auto horn relay on the starter and moved the connections on the solenoid to the relay. The wiring harness now provides enough current for the relay and the relay provides the high current for the solenoid. It has been working fine for 10 years.

[RaymondR]

If the buzzer sounded when you switched the key on but the engine would not crank it tends to suggest that there is a poor connection somewhere rather than a blown fuse.

[ski69sail]

Hi there

I have a yanmar 4jh3-te that displays a similar issue.

That is complete electrical loss after a few hours run time...the fault disappears with a turn on and off with the key..
Been looking for the fault for years...

So watching the post with interest..

Thanks

[Red Sky]

This won’t help the OP, but I was having an intermittent start problem on my 4jh3e. Cleaned all the connections, then changed the key switch, the start solenoid, no help. Traced the harness from the key switch to the starter and found a failing 30amp relay that wasn’t on the Yanmar wiring diagram, the boat builder had added it independently.

[jimbojonesbos]

It was indeed a fuse that was buried deep in electrical tape , I would not have known to look forward for it without your assistance.
Thanks!

[DIJ]

Yet another example of an oft used sequence for resolving an electrical problem
Step 1 check for a blown fuse, if no luck then
Step 2 make sure you checked properly for a blown fuse, if no luck then
Step 3 make sure there’s no fuse you were not previously aware of to check, if no luck then
Step 4 check everything else
I don’t remember et getting to step 4 very often, may be lucky!

[Calif.Ted]

On a Perkins the engine was running and it wasn't until I went to shut down that I noticed the gauge panel was dead. Stopped engine and discovered it would not turn over and restart. While trouble shooting and a lot of head scratching I discovered the fuse on a schematic and started diving into the electrical tape. I think it must have been on the wiring plan from the boat builder not the engine manufacturer's manual. When it happened on a Yanmar I just started looking for the fuse.