Just bought a D6C 10K6058, going over it and found a wire not connected. On further inspection I found it comes off a "green thing on the back of my oil pressure gauge. The green wire comes off the ammeter and is hot. The black wire is not connected to anything, but is sparks good if I touch it to chassis. What is it? Do I need to ground the black wire?
I don’t see that in the book, it’s definitely a pressure actuated switch, is there maybe an hour meter on the dash that they are using that oil pressure switch to operate?
Where does that green wire go.? I’m assuming the black wire is ground.
Are hour meters driven off pressure gauges? I've got an empty hole on the left side of dash, could be a former hour meter. Edit: Just did some reading, the oil pressure switch "turns on" when it detects pressure and starts the hour meter. When you turn off the engine it "turns off" stopping further clock time. I'm pretty sure you figured it out. Thanks, now I can play tomorow.
I’m going to guess the fuel pump driven hour meter isn’t working so they installed a voltage driven hour meter and an oil pressure switch is a very convenient way to operate one in this application.
Allis-Chalmers did this for many years on their equipment.
This pressure switch as already pointed out is to run the hour meter, the switch is often located on the later D6C and D series Tractors under the fuel injection pump screwed into the side of the cylinder block, this makes it very hard to replace due to the Generator/Alternator being in the way, the same pressure switch is used on some D8H Tractors that run Alternators to supply Induction voltage to make charging commence, this is in place of a red warning light that is common to use on other types of machinery. tctractors.