Yanmar 3GM30F Panel and Harness

[Jacksonboat]

Hi, I believe what I have as a panel from my Yanmar is called a "B type". Have noticed basically the only light that has ever come on is the "power" or Alternator light at startup. I do not get a temp or oil pressure light at startup as my manual indicates I should. My tachometer works some trips and doesn't on others.

What I am trying to figure out is where should I be looking first before rushing out for a new panel or wiring harness or both? Obviously I don't want to do that if I don't have to. (the engine is 1987)

Anything to suggest or any of the same experiences?

Thanks

 

[kloudie1]

Panel Wiring

Probably have loose/no connections mostly in the multi-pin connectors in the harness. I have attached a diagram of what I think your wiring looks like.. You would normally get a low oil pressure alarm and light but only a light for the "charge" .. so if your charge lamp is burned out and you have a bad connection in the oil pressure circuit (yellow/white wires).. You can check the sender by turning on the key switch and grounding the yellow/white at the oil pressure switch, just above the filter, I think. If you get an alarm doing that, your pressure switch is bad. if not, either a bad connection or a busted buzzer??

EDIT: I see that you stated that the charge lamp comes on.. so the low oil pressure circuit is where you should be looking. The high temperature lamp and warning should not be on.. As noted above, a quick check is to ground the oil pressure switch connector at the engine block. If the alarm sounds and the lamp lights, you have a bad switch.. if not then you have a bad connection (including a possible open as noted by Benny) in the yellow/white circuit. Or a bad buzzer

 

[Benny17441]

It would be an unlikely coincidence that an oil pressure sensor and a temperature sensor would both fail simultaneously. By the same token it would also be an unlikely coincidence that the idiot lights for oil pressure and temperature would both burn out plus the alarm buzzer at the same time. I would start by conducting a continuity test on the harness from control panel to engine. Perhaps it would be easier to conduct a visual inspection of that harness. Get down under the cockpit sole and check for cut insulation and wires specially where the harness takes a bend. What happens is that this harness can be become chaffed from being in contact with sharp fiberglass corners and hull flexing over a long period of time. You may repair any cut wires and add insulation to the harness. The visual clues are usually there but if you find none then conduct a continuity test. You may measure the voltage drop on each wire to determine if the harness is still good.

 

[Jacksonboat]

It would be an unlikely coincidence that an oil pressure sensor and a temperature sensor would both fail simultaneously. By the same token it would also be an unlikely coincidence that the idiot lights for oil pressure and temperature would both burn out plus the alarm buzzer at the same time. I would start by conducting a continuity test on the harness from control panel to engine. Perhaps it would be easier to conduct a visual inspection of that harness. Get down under the cockpit sole and check for cut insulation and wires specially where the harness takes a bend. What happens is that this harness can be become chaffed from being in contact with sharp fiberglass corners and hull flexing over a long period of time. You may repair any cut wires and add insulation to the harness. The visual clues are usually there but if you find none then conduct a continuity test. You may measure the voltage drop on each wire to determine if the harness is still good.

Perfect this is all good stuff - to add to it and perhaps clarify

I put the key in, turn it, I get the buzzer and the charge lamp, press the start button and engine starts without fail, the light and buzzer go off. Has worked this way since I've owned her (three summers now)

 

[Stu Jackson]

Many of our boats came with HORRIBLE connectors for the wiring harnesses between the cockpit panel and the engine. THAT'S where you need to start looking. Many of us have simply replaced those connectors with terminal strips, Euro strips (mini terminals) or butt connections. In most, if not all cases, the wiring is fine. It is the connectors that come from the factory that are rotten, literally.

doesn't matter whether it's a Hunter, Catalina, B, J or much anything else. Darn it...

 

[Jacksonboat]

Many of our boats came with HORRIBLE connectors for the wiring harnesses between the cockpit panel and the engine. THAT'S where you need to start looking. Many of us have simply replaced those connectors with terminal strips, Euro strips (mini terminals) or butt connections. In most, if not all cases, the wiring is fine. It is the connectors that come from the factory that are rotten, literally.

doesn't matter whether it's a Hunter, Catalina, B, J or much anything else. Darn it...

I'm hoping that is the case - 8 am shall be the hour of truth!!! Thanks it's driving me nuts

 

[HMT2]

I put in a new panel for aesthetic reasons (and it was falling a part). Once you get the panel off the bulbs are easy to change. I would check the connections there before I ran around chasing things in the wiring harness, mine worked but were pretty corroded. Also, you should have a switch there that when you flip it down it lights your tach and when you flip it up and hold it all your other light should light up (oil pressure and water temp). There should be an extra bulb in the panel once you get it off.

 

[Jacksonboat]

Perfect yes I will have a look at bulbs first. And yes I failed to mention that I have the switch as well of course but all it lights up it seems is the tach light (which works) but the tach is flaky - sometimes it reads without problem, some trips absolutely nothing. I've grown accustomed to the sound and speed so sometimes I don't even look really but my ultimate goal here is to actually have everything work the way it should.

 

[HMT2]

I had to replace my tach. It never worked. New tach fixed it. Might want check that the connections in the tach sending unit are clean and strong.

 

[Jacksonboat]

I had to replace my tach. It never worked. New tach fixed it. Might want check that the connections in the tach sending unit are clean and strong.

Well strangely enough connector to the tach seem sound . What was add though is that the bulbs behind temp and oil had been completely snipped and the wire re-run to aftermarket temp and oil which don't work at all. Looks like I will have to unhook the aftermarket stuff and rewire the original to find out if they work at all. Painful.

 

[HMT2]

That's pretty strange. My understanding is that the senders for the warning light/buzzer are like switches they are off until a certain event (pressure or temp) then they are on. To get data you have to put in senders that send temp and pressure. Good luck. In the back of my engine manual there is a wiring diagram for the b type panel.

 

[Mhoffpapa]

I recently changed all the batteries in my Hunter 336. The day after the "idiot light" in the instrument panel came on. With the engine running the batteries all show 14.5 volts. Thus I conclude the alternator is working. What could be causing it? I have a Yanmar 3GM30 F. The boat is equipped with a single solar panel.