Farmall Cub

What is the easiest way to check the key switch without removing it. Put a new battery in it and ...nothing. Switch is a bear to get to. I know I need to check the safety switches too. By the way, I'm electrically challenged. (among other things) Thanks, Grump

First two places to check for voltage are the "safety starting switch" and the solenoid "magnetic switch". Fault in either one will prevent the engine from cranking over.

Typically ignition switch is wired in series with the safety starting switch then the solenoid.

The safety starting switch Eugene mentioned is a common problem as are broken wires. Make sure the tab on the clutch linkage is making contact and depressing the safety switch. Take a cheap test light and follow some circuits and see if you can eliminate wiring problems and isolate the problem.

Good luck!

Here is the wiring diagram for a 106.



First off, Check you battery cables. Double check your ground cable. With a volt meter, touch the positive terminal on the battery and simultaneously touch somewhere on the frame of the tractor (a bare spot with no paint or rust), you should have a solid 12-volts on your gauge. If not, the ground cable is bad, but do the same test in a few different places to make sure you've got a good reading. Make certain that the positive cable is in good shape, check with a volt meter that you have 12-volts at the starter lug where the battery cable attaches. It's always hot. Touch one lead of a volt meter to the terminal, and another to the frame of the tractor somewhere. You should have full 12-volts there, even with the key off.

Second, if you've got headlights, turn the key to on, then turn on the headlights and watch the Amp gauge. It should deflect or move a little either when you turn the key on or when you turn the lights on. If you get no deflection it's likely the key switch (although they typically don't fail).

Third, if the second test passes (amp gauge deflection), take a piece of 12-gauge wire about 2" long (solid copper wire like house wiring works best), strip both ends about 1/2", and form into a U. Underneath the tractor, look up and find the clutch pedal switch. Unplug the connector and push your U into the connector on the wiring harness side (not the switch). Now see if it will start. If this works, then it's the safety switch that has failed. (This is the most likely problem area and may actually be worth testing first, however the amp gauge thing is kind of a given/easy test).

If you're not getting anything, no amp gauge movement, nothing when jumpering the safety switch, then it's time to pull the switch. It really should not be hard to get to. You should be able to reach in from the engine side, back under the dash to get to it. I've taken several out this way. It takes some patients, but it can be done. Another way may be laying under the tractor and reaching straight up into the dash tower, but I think this is more difficult than coming in from the engine area.

These tests should get you some good information, or let you diagnose the problem.

Thanks for the info guys. It's supposed to warm up this weekend and my son is getting married so, I'll get to it maybe next week. Grump.