We have an oil pressure light and a high temp light and an alarm buzzer on our boat. The PO had put a single pole oil pressure switch in and bridged all 3 wires onto the one terminal. The warning lights and alarm were not working and I suspected that this change of switches/wiring had the effect of killing the warning lights and alarm buzzer based on my reading of the wiring diagram.
I put in the correct oil pressure switch from Universal and fixed the wiring as it is shown in the wiring diagram and the oil pressure light and alarm buzzer came to life when ignition is turned on as I suspected they would. However, the high temp warning light does not come on with the ignition. The high temp light works when I put power to it so I know the bulb is fine.
Personally I think the way they have tied together the warning lights/alarm buzzer/fuel pump/oil pressure wiring is way too complex and not necessary. I intend to eventually try to by-pass that fuel pump/oil pressure switch interconnect stuff without killing the alarms, but for now I want to get it all working the way the wiring diagram shows it to be. In trying to decipher the wiring diagram I don't think there is anything that would turn that light on when the ignition comes on, though I'm not sure about that.
Just wondering if any owners of boats similar vintage to ours can tell me whether or not the high temp light comes on when the ignition is turned on and goes out when the engine starts?
You know Bud, I too have wondered about those warning lights as well. I will be watching this thread for others' comments.
Glenn Druhot
Carpe Diem
New Bern, NC
35* 6' 10" N / 77* 2' 30" W
2001 C36, Hull #1965
Std Rig; Wing Keel; M35B
Bud,
I'm not 100% sure, but I don't believe the engine panels are that "smart". Most cars today are computerized, and have a self-test feature whereby all lights go on for a few seconds, and then only the appropriate ones stay lit. I believe that the oil pressure light and/or buzzer goes on when you turn the key, because the circuit has been energized, and there is no oil pressure. On the other hand, when you first turn on the key (assuming the engine is cold), the engine temp is not high, so the high temp alarm does not go off.
Tom Sokoloski
C36/375IA Past Commodore
Noank, CT
I have to agree with what Tom has to say. Looking at the electrical drawing over coffee this morning. The oil sensor light would come on because pressure is not making the switch thus completing that circuit.
The the high temp light should not as this circuit is not complete. The circuit is complete once the engine is overheated. If you do see the light come on. I would want to have the sensor checked out or replaced.
Randy
Randy Sherwood
Mutualfun 1990 # 1057
T/R W/K M35a
Home. Charlotte, Mi.
Boat. St Augustine,Fl.
Thanks for the replies Tom and Randy, that was my belief as well but I wasn't 100% sure that my interpretation of the wiring diagram was correct. Always good to have a 2nd opinions rather than venturing off in the bliss of one's own ignorance.
If you wish to test the high temp sensor switch, the classic method in to remove the sensor, attached an ohm meter to it (one lead to the terminal and the other to the body) then put it in a pot of water and heat it until it boils or the contact is made. If it boils before contact, you [I]may [/I]need a new sensor switch.
Some sensor switches may close contact at temperatures above boiling, 225+ or so. The body may have the temperature engraved on it or not.
To be fancy, you can use a thermometer to determine the actual temperature that contact is made.
You can also use a battery and bulb in place of the ohm meter.
I run a 200 degree sensor switch on Tara. And, yes, it works! Nothing like ending a day on the water with Nurse Judi with a strange noise blaring, high temp light shining and steam pouring out of the cabin. An M25 can dump its coolant REAL fast when a hose clamp lets go!
The unlimited towing package from BoatUS sure came in handy that day!
:D
Fair Winds,
Glenn "Chooch" Jewell
Nautae Luna 1232 (RIP Tara 389 Hurricane Sally 2020)
GO NAVY - BEAT ARMY!