MF165 Charging Systems

Installed the alternator....not charging. So I thought it must be the voltage regulator. replaced it , still no success. Then a guy at my massey dealer said its probably the Oil Pressure switch on the back of the oil pressure gauge. So I by passed it , still no charging.

Then I started playing around and now understand that the #1 wire is the field sensing wire, but I wasnt sure where to connect it. It needs power when the tractor is running to create the field , but not when the tractor is off. ( do I understand this right?)

I read the YT web site some more and saw a post for an MF35. It suggested I connect the white wire to the wire that runs between the oil pressure switch and the Ammeter ( generator guage in my case).
Did that , the tractor was charging yesterday, thought I had success. When I went out this evening to the start up the tractor. TOTALLY dead. I guess this connection caused the battery to train even though the tractor wasnt running. Am I connected to the wrong side of the Oil pressure switch?....

Where should I connect this thing? I thought maybe to the ignition switch, but its only a 2 post switch. It only powers for the moment that the key is turned to turn the tractor over. Should I swap the alternator and get one of these self Exciting ones?

Any and all suggestions are much appreciated.

Donovan from Wisconsin

I was rigged to the oil pressure switch and the battery still drained. does this mean that my oil pressure switch probably isnt working? I had my oil pressure switch disconnected, now I lost track of which connector went on which side of the switch...so I assume its a simply switch that is closed or open. So I should connect my Alternator Excite line to what ever side the Ammeter hot wire is not on I suppose?

I reply to bob earlier asking what post I could put it on, on my ignition switch , but this diesel is only a two post switch...one goes to the Ammeter , the other to the solenoid...not sure where I should put it if I go that way

That switch is what operates the charging system and guages. If it is bypassed, the guages and charging system will always have power unless you pull the wire off everytime you shut it down.

Donovan from Wisconsin

This picture of Bob's show's how to connect your alternator wires. Note the diode he has in the circuit to stop the battery drain or backfeeding
voltage to a tractor with battery ignition. Hal

The purpose of the diode is to prevent current from feeding OUT of the alternator's #1 terminal, into the ignition system of a "gasser", or the fuel solenoid of a diesel (if so equipped), preventing the engine from shutting down when the key is turned to "off".

The diode also prevents the alternator's internal voltage regulator and diode trio from being damaged by excessive current flowing through them, should there be a fault in the circuit from the alternator's large output stud to the battery.

My ignition switch has 2 posts on it.
1 to the ammeter ( which I think has power to it all the time ) and the second to the Solenoid.
I assume by the term load side of the ignition, that this is the side that goes to the solenoid?

Appreciate everyones help...this old tractor would be a challenge without you guys.

Treefarm