CA Allis Chalmers Wiring

C M Behounek

New User
I got my generator back from getting fixed. I traced all the wires for bad spots. I got a new ammeter. Took the light switch out and cleaned it up. Put new connections on everything, cleaned all terminals. My instrument box is grounded good, because my magneto ground switch works. I put on a new cut out relay before I got the generator fixed and wasn’t sure if I screwed it up so I took the one off my wd 45 not sure if that one worked either. I’m not seeing the needle move at all on the ammeter. so I put the older relay on the generator thinking it would work and still no needle movement. The generator is really hot after the engine runs some. hotter than the block. I read all the information in the operators manual and hooked all terminals as it says and shows. 1. The neg. side of the ammeter goes to the BAT side of the relay. This is the white wire inside the box not the short white wire, and is actually yellow by the time it gets to the generator. 2. The field wire terminal on the generator goes to the resistor on the light switch, brown wire on the bottom of the switch. 3. The GEN terminal on the relay is hooked to the most later terminal on the generator, this is a 2 inch wire. 4. The neg. side of the ammeter goes to the "B" on the light switch, this is the small white wire in the panel box. 5. The pos. side of the ammeter goes to the starter switch yellow wire. In All 3 positions of of the light switch I get nothing. I don’t want to run the engine until I fix this in fear of damaging something. Do I have things connected right? could one of my components be bad? Am I missing something? Why dose the generator heat up? Do I have the wrong parts? Please Help Thanks Chad

Is polarizing where you momentarly jump a wire from the BAT terminal to the GEN terminal of the relay? I tried that with the newer relay befor I put the old one on it and had no movement on the needle that is if I did it right but I ran the tractor befor I did this. This book i have says to do it befor starting the engine? Would this test not have worked?
I think the jumper is from the field connection of the generator to the hot lead of the battery. If this connection is made, the generator should charge at full capacity. After it starts charging, it should continue after removal of the wire unless there is a bad component. Are you certain that your gauge is good? When you turn on the lights, does the gauge show discharge of the battery? If you have battery ignition, do you get a discharge when you turn on the ignition? If you don't see these discharges, you may have a bad gauge.

I may be over my head. This is the way I have gotten them going - may not be best way. Be nice if John T or Soundguy checked in on your problem.
it sounds like you have the thing wired right. generator "G" to the relay. relay out to the amp meter neg side, positive side to the starter which is connected to the battery. i would guess it is getting hot because it is at full charge, but the amp meter should show that. i think i would take the battery wire off the light switch that goes to the ampmeter negative side and try again. if that dont work, i would touch the "F" side of the generator to the tractor frame (ground) and bypass the light switch ground and try that.. my guess is somehting wrong with the light switch, wrong terminals, or poor ground on it.
Chad, if the ammeter is good n NOT stuck a magnet passed by it should make the needle deflect..... An ammeter is near a dead short continuois circuit across its terminals if its good.......If wired right if you turn on lights when engine isnt running IT SHOULD SWING OVER TO -DISCHARGE. If it swings to + charge its wired backwards n needs the wires swapped

An ammeter has ONLY ONE wire on its SUPPLY terminal which gets to the hot ungrounded battery post, often at the starter switch where the big battery cable atatches....

Its other LOAD terminal feeds hot batetry voltage to loads like lights (often the BAT input terminal on a light switch) (and ignition if a coil ignition) PLUS it wires to the BAT (NOT to the genny) terminal on the Cutout Relay.

The other GEN/ARM terminal on the Cutout Relay wires to the ARM post on the Genny.

Gennys FLD post wires to the charging resistor circuit on the Low/High charge type light switch.

After shes wired correct you need to Polarize the genny BEFORE you start her up.

John T
John, I moved the needle on the ammeter with a magenet and it moves good. I put a new ammeter on last summer when i started all this process. I do not have lights to test the charge and discharge like you describe. I have all the terminals wired as you describe. Maybe I have a bad component? I am prety sure I have the field wire terminal on the generator to the right spot. It is hooked to the bottom of the switch next to the terminal with the wire raped around it. I think my switch may be bad. How do I polorize the generator and when?
The battery wire on the light switch is that the real short one? Take it off and then what should I do. Do I leave that wire off during the next test. Would the F side of the generator be the field wire terminal, touch the F side of the gen to the frame or the wire that came off it? do I do this while the tractor is running?
A way to tell if the genny is working regardless of the Low/High switch function is when the tractor is running dead ground the gennys FLD post n see if she charges then?????????? If so but NOT when wired to the Low/High switch the switch is bad orrrrrrrrr its not well grounded. When you dead ground the gennys FLD post that makes her HIGH charge if everything else is okay. The switch dead grounds it (if good and is grounded itself to dash) for HIGH charge but grounds it via a series resistor (one on the switch) for LOW charge.

Then a way to test the cutout relay if its still NOT charging (when running) even with a dead grounded Field is to leave the FLD grounded and by pass the cutout relay function by jumping its BAT to its ARM/GEN. If it charges then but NOT otherwise the cutout relay isnt latching in

With the FLD dead grounded and the relay by passed if still no charge the genny itself is bad assuming all else is good n wired correct

To polarize the genny momentarily flash jump by pass the Cutout Relay by jumping its BAT input over to its GEN/ARM output and you ought to get a spark.

John T
By testing the generator; dead grounding the FLD post; do I just take a short piece of wire and touch one end to the post and the other to the frame? Do I unhook anything when I do this? do I need to disconect the wire from the gen. FLD post side or the resistor side of the light (high-low) switch, or both. Then do I leave it this way when testing the cutout? I do understand how to bypass that. but not how to test the gen.
YES, when shes running simply dead ground the FLD post to frame ground and no need to remove the wire up to the light switch. YES leave that in place when doing the relay by pass.

Click this to a link with my complete Troubleshooting Procedure and use the cutout relay procedures. Its on the Farmall pages but still the same for your tractor.

John T
John Ts Troubleshooting Procedure

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