Most of the engine gauges on my 1979 J/30 aren't working. I have a cluster of 5 guages - Tach, Temp, Oil Pressure, Voltage and Engine Hours. The only two that are currently working are the Voltage and Engine Hours gauges. I have gone through the wiring diagram on the J/30 Class website and everything seems to be hooked up fine. I was wondering if its possible to hook up an Ohm meter to the connections on the back of the gauges with the engine running to make sure there is actually something going to the gauges - and if not, then I know the gauges are bad, and not a sensor. Does anyone know what kind of readings I should be getting on the gauges?

Thanks in advance.

Do you have a lamp test switch on your instrument panel? If so, flip the switch to test the bulbs. If the lights dont come on, then you need to replace the bulbs. If they do, then the problem with the temp and oil pressure is probably the senders on the engine. Wiring typically fails last. As far as the tach goes, the sender is near the flywheel on the back of the engine. It should have a specific resistance (which escapes me right now). If it doesnt meet this resistance, the sender needs to the replaced.

Since all this stuff is out, you may have a break in the wiring harness. Get some help to check the continuity of the wiring from the source to the panel. It might just be the power source to the panel.

Isnt troubleshooting electrical systems fun

Thanks for the response. I do not have a lamp test switch on my guages. There aren't any of the red indicator/warning lights on the console. I've seen what you are talking about though. Do you know who I would talk to about the resistance on the tach and other guages. I've looked all over on the internet with no luck.

Thanks again.

I bought a book from Amazon about Yanmar diesel engines that covers all the diesels used on J30s among others. Its called Yanmar Inboards 1975-98 Diesels. Just search Amazon.com. They want $25 for it. Its worth every penny.

If your panel is at all similar to later J30s, you should be able to pull the panel out and pull the various bulbs to check their resistances. All you are looking for with the bulbs is continuity. If all the bulbs and other items requiring power on the panel are not functioning, it may be a lack of power to the panel itself. Turn the ignition switch on and check for 12 Volts on the power wire.

As for the tach sender, I'll send myself a reminder note to look up the resistance check value in my book. I'll post it back here soon along with anything else I might be able to find.

Scott, The tach sneder resistance should be 1.6 kOhms. Hope this helps.