Ignition switch fault tracing - HELP!

[FarmerJoe33]

Hi everyone. My first post here. I've got a 1970 IH McCormick 434 tractor. Went out to start it the other day. After the glow plug indicator began burning bright, I went to turn the key fully and nothing. When I went back to glow plug warm-up position, also nothing. Checked the headlights and got nothing too. Battery was fine two days before, running normally and no problems with starting. Is it likely that the starter switch is burned out somewhere or that one of the circuit breakers is blown or some other issue? This is a ground positive wiring so it's a little new to me as to how all the electrical systems function and why the lights would be non-responsive if the ignition switch is faulty. Any ideas appreciated.

 

[K5lwq]

Could be a cable or a connection failure. I would start with load testing the battery. Then look for a inline fuse. Then check every connection point for corrosion.

 

[AWSubie]

Check to see if you have at least 12.4 volts at the battery. If so, bypass the ignition switch by going direct to starter solenoid with a pair of jumper cables.

The starter should turn unless there’s a solenoid issue.

When doing this make sure the transmission is in neutral.

 

[jaxs]

Do you have a multimeter?

 

[Rebeldad1]

if everything went dead all at once its probably a connection to the battery or ground. and yes a battery can go bad over night.
like anything electrical the next time you use it could be your last.

multimeter is your friend here

 

[Boss 302]

Yup, like stated either bad battery or bad connections

 

[FarmerJoe33]

Thanks everybody. I found the problem and I have to say that ground positive wiring (also known as Lucas wiring) is weird. The problem was a loose connection to the starter. I didn't see it at first, so I pulled out the ignition switch, cleaned up all the contacts and put it back in. Battery was fine - I have a digital charger that reads load and amperage. The battery in this wiring goes straight to the starter first, then that routes to a circuit breaker where all the other components jumper from there - lights and ignition switch. Very different from what I expected. Anyway, she's back to running and all I have to do now is find the thousand possible places where the small oil leaks are forming