Massey Ferguson 165 alternator wiring

Ford8600@

New User
Need help with an alternator question. I'm wiring in a Delco 3 wire alternator but for some reason when I attach the excitor wire to the post for the coil on the ignition switch,the light won't turn on. It is a 194 bulb and socket. It will turn on though when I turn the key in the on position and I touch the wire that should be attached to the coil post and touch it to any ground on the tractor. What am I missing?
 
One end of the lamp circuit should be connected to the #1 terminal on the
side of the alternator.

The other end goes to the ign (coil) side of the ignition switch. Be sure the
wire is connected ahead of any resistor or resistor wire, it should have very
near battery voltage with the ignition on.

To test:

Ignition on, engine not running, the light should be on.

Engine running up to speed, the light should be off.

Anything different indicated a problem with the alternator.
 
(quoted from post at 20:29:15 05/22/22) Need help with an alternator question. I'm wiring in a Delco 3 wire alternator but for some reason when I attach the excitor wire to the post for the coil on the ignition switch,the light won't turn on. It is a 194 bulb and socket. It will turn on though when I turn the key in the on position and I touch the wire that should be attached to the coil post and touch it to any ground on the tractor. What am I missing?

Do you have the #1 "Excite" and #2 "Voltage sense wiring connected properly at the alternator?

The #2 terminal should have battery voltage at all times.

With the battery connected and the lead to the #1 terminal DISCONNECTED the #1 terminal should read "0" Volts.

Reconnect the lead to the #1 alternator terminal, with one side of the indicator lamp connected to the ignition switch and the switch "ON" the #1 terminal of the alternator the alternator should be providing a ground path for the light and it should illuminate 'til you start the engine and the alternator begins to charge.

I'm thinking perhaps you have the leads swapped at the #1 and #2 alternator terminals.
 
Mornin Ford, you ask

but for some reason when I attach the excitor wire to the post to the coil on the ignition switch, the
light won't turn on. It is a 194 bulb and socket.

Are you sure its connected right?? The little 1(R) alternator terminal on the alternator goes the INPUT
side of the coil (OR ignition switch terminal that leads there and becomes hot when switch is ON) that's
the coils side wired to the ignition switch NOT the side to the distributor. When the ignition is turned
ON (If you're wired right?) voltage should be present and then of course IF THE BULB AND WIRING IS GOOD it
lights up. Test to see if the coils INPUT and the ignition switches terminal that leads there, has voltage
with ignition ON IT HAS TO FOR THE IGNITION TO FIRE.

Many wire the 2(F) alternator terminal right down to the big main output stud.

John T
 
could it be my ignition switch back feeding? I have the lamp and wire hooked correctly not the incandescent bulb starts up but it won't turn off. Could it need more resistance?
 
On those Delco SI family of 3 wire alternators Ive used a small incandescent marker lamp (or a diode or a
10 ohm resistor) always worked fine yet an LED has too much resistance. If its connected to the ignition
switches IGN output that leads to the coils input (NOT output side to distributor) and then to the small
1(R) terminal on a GOOD WORKING CORRECT WIRED ALTERNATOR and the switch is good, that should suffice for
adequate excitation and go OFF if the alternator is working and wired correct.

NO I dont think it needs more resistance ... Is it wired like this ?? maybe the alternator is bad??

Small 1(R) excitation terminal gets the excitation via the lamp
Small 2(F) voltage sense often wires to the big main output stud on the alternator

John T I am NOT an alternator expert see what the other fine gentlemen have to say
 
Is the light socket you have for your indicator light an isolated ground base? It should have two wires. One socket wire goes to switched power (generally the IGN terminal of the ignition switch) and the other socket wire goes to the #1 spade terminal of the alternator. I don't see why you would hook to the coil input terminal to excite the alternator if you are using an indicator light. Unless you are running wires back to the dash from the coil for the light or have the indicator light somewhere on the motor between the coil and alternator in that wire, it isn't going to work as I envision what you are describing. If you have an ammeter in the dash, I will suggest you forget the indicator light and put a diode in the wire between the coil and #1 alternator terminal. There are several types of pigtails, with a diode already in them, available that plug right into the alternator.



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