The wires going into the switch are part of the ignition circuit. The wire from the push start button goes into one side of it and the other wire coming out the other side gives power to the magnetic switch strapped to the starter that then gives power to the starter solenoid. When I try to start it, power ends at the input of the switch under the floorboard. I don't know what function engages the ball bearing on the switch, but it seems not to be engaging it. I did a continuity test on the switch and when I push the ball bearing in, current flows across it. Could the switch still be bad even though current goes through? Not enough current? Mostly I just need to know what it is and what engages it, so I can figure out why this CAT won't start. It's been sitting for 10 years or so. My Pops is not well and I'm tuning it up, getting it running again before he can't enjoy it anymore. I've got all the fluids changed and new battery and new filters all around. Went to start it and ran into this electrical issue. Any help I would appreciate so much.
Drop the SN on the machine and guys with access to SIS can root thru the wiring diagrams for you.
Thanks for that tip. Here it is. 45V21748
Here's the data plate.
I feel like it might be some kind of safety switch. But I don't know what engages it. I'm wondering if I can bypass it temporarily...safely.
I found a wiring diagram in the service manual. I'm not very good at reading these. I'm guessing the mystery switch might be the transmission safety switch? If so, how to engage it?
Looks like it's just a neutral safety switch to prevent you from starting in gear. you can bypass it easily by just connecting the wires together at the switch( just put both wires on one terminal) but make sure you have the machine in neutral before starting or other precautions are in place!!! There should be a plunger in side the case pushing the ball in the switch when you move the tranny selector to neutral... switch could still be bad even though an ohm meter shows continuity especially if the machine is left in gear a lot sitting unused the terminals inside the switch could be corroded... also could be the linkages from the selector may be too worn to get things where they need to be for the switch??? With the switch removed carefully push a pen or similar in then easily move the shift lever to see if things are actuating.
Oh man, thank you so much for the detailed response. That is exactly what I needed to know. I almost paid $45 on just answer. Thank you so much.
BTW that Serial Number plate that you took the photo of is the engine S/N not the tractor .......... the tractor SN should be 6Nxxxx. The transmission safety switch is clearly marked on the wiring schematic that you posted the photo of - centre RH side just below the alternator. Unless the linkage inside the transmission activates the switch (indicating the transmission is is neutral), it disables the starting circuit. Try removing the switch and push the plunger. Measure across the contacts with a DMM to check if the switch is opening and closing correctly. If it is permanently open circuit - replace it. If it is working correctly - you could have bigger problems. The switch is Part Number 9P-9520, price about $22 from your local Cat dealer.
Turn your start switch to start and wiggle the transmission shift lever in neutral and you may find the sweet spot. Bob