Broken Prong on Oil Pressure Switch

Ralph Johnstone · Apr 3, 2014

You're Best Bet ......................

............................. would be to check with a parts supplier for your particular engine. You'll be looking for the same thread pitch and diameter as your engine requires and this may not be available across the counter for many pressure switches.

Shown is a picture of a pressure switch (Yanmar 2GM20F) with the wire disconnected. It has the solid post for attaching a ring terminal.

Ralph Johnstone · Apr 3, 2014

DaveJ said:
I was just wondering if there is an upgraded or better part out there.

I see what you mean about this not being the sturdiest of electrical connections. It's bound to be broken again in just snagging it during regular maintenance.

Any chance you can anchor the wire very near the terminal so as to reduce the chance of snagging it ?

Tom J · Apr 4, 2014

I got my replacement switch at NAPA. Just bring the old switch with you. No problem removing the switch with the engine off, maybe a little oil dripping out of the fitting. It does help to secure the wires with zip ties.

pk104 · Apr 5, 2014

I got mine at NAPA also at a much better price then Universal. Before you go look up the oil pressure limits. It is some where around 6 to 13 but I forget the exact number.

Albanach · Apr 5, 2014

I had to replace with a locally bought 3 prong switch. My problem with the old switch had been that one of the wires’ connectors was continuously falling off-until one of the prongs eventually broke off anyway.

To lessen this problem somewhat, I soldered the female connectors (not the wire) of 2 longish pigtails to the prongs. The pigtails’ blade connectors then attach to the electrical circuit wires’ female connectors. The end effect of this is a firm connection at the switch, with the impact of the engine’s vibrations on the circuit’s blade connections dampened by distance. A check of the blade connections and any possible re-connection is also more accessible.

The soldering has to be done carefully though, so as not to fry the switch.

c130king · May 15, 2014

Does anyone have any photos of where this switch goes? I have the same issue...no low oil pressure warning horn or light. Replaced the horn. So now I have new Oil Pressure Sender switch. But not sure exactly where it goes yet.

Appreciate any photos or descriptions on how to do this.

Cheers,
Jim

paulj · May 15, 2014

Pictures...............

paulj :troll:

c130king · May 15, 2014

Thanks Paul. I take it that is lower forward port side.

That switch does not look exactly like what I got. There are 2 prongs on one end and a threaded post on the other.

Guess I screw the old one out and screw this new one in and then attach the 2 wires to the two prongs. The prongs look like the male end and will need female plugs to go on them...definitely not screw in wires as in your picture.

Will try to replace this tomorrow. Along with my new Oberdorfer Raw Water Pump and 12-volt horn (old one fell off 2 days ago...mounted under starboard stern rail seat).

Thanks,
Jim

R. Chapin · May 15, 2014

I have the male/female configuration and it has broken twice already. One time when a prong broke off the loose wire shorted things out and I was unable to start my engine. At that time I did not know about the reset button on the engine.
I like the connections on Paul's switch. If I have to replace mine again, that is the direction I will go

c130king · May 17, 2014

So installed the new oil pressure sender and still get no low oil pressure warning horn or the red warning light. Still going to have to do some trouble-shooting to figure out the issue.

Must be electrical connection somewhere I guess.

Cheers,
Jim

woodster · May 17, 2014

c130king said:
So installed the new oil pressure sender and still get no low oil pressure warning horn or the red warning light. Still going to have to do some trouble-shooting to figure out the issue.

Must be electrical connection somewhere I guess.

Cheers,
Jim

the oil pressure side of those switches do not set the alarm off when turned on ...you may have a duel connection switch that one side sends oil pressure voltage to the gauge and the other connection works the alarm and light ......the alarm side is the side that when oil pressure builds up in the oil system the pressure breaks the ground to the alarm and light and when the oil pressure drops back down to about 2-4 lbs the ground reconnects and turns on the alarm and light

c130king · May 18, 2014

Woody,

Yes, I think I understand that. All I know is I used to get a low-oil pressure warning horn when the key was on the engine was cold (low oil pressure). And that horn would go out very quickly after the engine was turned on.

Now I don't get that.

Will check connections on the switch itself. Check the connector bus behind the engine panel. And check connections to the light and the horn.

Anything else to check for issue?

Cheers,
Jim

woodster · May 18, 2014

c130king said:
Woody,

Yes, I think I understand that. All I know is I used to get a low-oil pressure warning horn when the key was on the engine was cold (low oil pressure). And that horn would go out very quickly after the engine was turned on.

Now I don't get that.

Will check connections on the switch itself. Check the connector bus behind the engine panel. And check connections to the light and the horn.

Anything else to check for issue?

Cheers,
Jim

does your alarm buzzer work at all ...if not check it directly and see if it is working

c130king · May 18, 2014

I just replaced it. I assume it works. But it is one of the things I will be checking.

The reason I replaced it is because the old one did not work during my recent...how shall we say...buffoonery. Turns out when you motor around the harbor for 30-40 minutes without the raw water through-hull valve open the motor will overheat. And the raw water pump turning for 30-40 minutes without water will melt the impeller.

Overheat warning light worked fine. Just never noticed it until too late.

;-)

Cheers,
Jim

woodster · May 18, 2014

make sure all your grounding is good as well some times it not the power wire but the ground wire that is the bad connection...good luck

CraigS · May 20, 2014

Addition Impact

Don't forget that the way Catalina wiring is set up, that an open prong on the oil pressure switch also means that the fuel pump stops working. When you get down to about half a tank of fuel, the level is even with the injectors, etc and gravity no longer provides a push to the engine. Had this happen in the open Gulf and needed to wire the 2 wires of the oil switch together to activate the fuel pump.

c130king · May 20, 2014

Is there a way to test the continuity of that pump circuit?

CraigS · May 21, 2014

The "GlowPlug" position of the key switch will cause the pump to run (even if the oil pressure switch is bad). It will also run in the normal ON position if the 2 wires to the oil switch are jumpered together. It is hard to hear the pump with the engine running, but the wire to the pump from the oil pressure switch will have +12 volts on it if the switch is working properly with engine running. I carry a small piece of flat metal that the 2 female connectors of the switch wires can fit on either end to hard wire them together in case of oil pressure switch failure (after verifying I have oil on the dipstick).

Broken Prong on Oil Pressure Switch

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