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Discussion Starter #1 (Edited)
I'm troubleshooting the electrical system of a LT133 w/o the aid of a tech manual. Have a 3 amp schematic but not sure if my LT133 is 3 amp or 15 amp.

Symptom:
won't crank (not even a clicking sound from solenoid)

Diagnostics performed:
tested battery voltage - tested ok (12.4 volts)
jumped battery with known good auto battery (auto not running of course) - still won't crank
tested continuity of ignition switch with ohm meter - tested ok
have continuity between ignition switch and solenoid (purple wire)

Without a manual I'm unable to identify the relays and switches.

What is the purpose of the PTO switch and where is it located? It appears that it needs to be in the OFF position in order for the solenoid to work. If it's in the ON position, current from the neg side of the solenoid will need to run through a reverse biased diode (V1) to reach system ground so it looks like no current will flow. Any help on the function of the PTO switch and its location is appreciated.

Also where is diode V1 located? What is X3? Is it a component holder of some sort?

Any help is appreciated. Thanks.
 

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The purpose of the pto safety switch is 2 fold. #1, it keeps the engine from cranking with the pto lever engaged. #2, it grounds the ignition coil if you get off the seat, even with the parking brake set.
The pto switch is located under the dash panel. Open the hood, look up near steering shaft. You will see the pto lever and aslo a flapper bolted onto the pto lever shaft. that flapper should contact the pto switch. its a gray push button switch, with 4 wires. If you are not cranking also chech the parking brake switch. parking brake switch is same switch as the pto switch and is located below the battery, on the brake pedal side. Just open the hood, look down on the frame while actuating the brake pedal and you should see it.
 

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Sorry... V1 diode is located on left side under hood where the relays are below the battery. It looks like a big fat Chicklet piece. Red in color. The X3 is a designation for a connector. In this case its the connection where the diode plugs in to the main harness.

Side note, all left and right designations are from the seat position, or standing at the rear of the unit facing forward.
 

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Discussion Starter #4
Thanks for this info. I get it now...PTO lever engages the blades. I toggled the PTO switch manually a few times, unplugged the connector from the ignition switch and cleaned it. Disconnected the solenoid wires and put the battery on a charger for about an hour. I decided to check the voltage across the solenoid so threw everything back together and when I turned the key to start, the engine turned over! Amazing what a good cleaning will do. Maybe recharging the battery gave it enough juice to crank. Anyway, she starts now but unfortunately, I don't really know what I did to fix it. But I'm a happy camper!

Thanks again for the info. I'll be ordering a tech manual TM1695CD soon. Hopefully that will have some diagrams of component locations.
 
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