By pass the switch with a wire

Well I guess you'd have to check each one with a VOM or continuity tester. If your mower happens to be equipped with a interlock module, that may be the problem and switches may be OK.

If you are having a problem getting the starter to activate, use a jumper wire between the cable coming from the battery to the starter solenoid and the small terminal on the starter solenoid. If the starter solenoid clicks and starter engages, problem is in safety switches or ignition switch. If no click, no action, problem is likely elsewhere or two or more problems.

Need more info.

Walt Conner

"How can I check if all saftey switches are working or not."

You need a schematic of your whatever it is you have so you know if the switch is normally closed, normally open or some combination thereof for multiple contact switches. Than you use a volt/ohm meter, test light or other means to verify the switch is doing what it's supposed to be doing under the condition thereof contained within itself to be determined upon continuation of various test procedures certified to be correct by the universal test procedure committee to be selected by a majority of the voters present unless properly certified proxies have been registered by the ad hoc select panel at their predetermined meeting to be selected at a date to be announced through the "normal" channels.
Don't be so vague!

First pull off a plug and check for spark. That would be a good start and would tell you that all the safety switches are working

Zoomie, the title says won't turn............

With no info, it is silly to go too deep.
This is likely a trolling post anyway.

Fish

Don't know about new LT, but the old ones are like a light switch. Either it's on or off. Place a multimeter on the two prongs. Do you get continuity??? yes or no. Activate the switch, read the meter??? do you get continuity???? yes or no. If the answer is yes or no in both positions this ususally means the switch is bad unless you have more than two wires feeding the switch.

If it's a older craftmans I would first check the manual blade engagement switch. It's a plastic switch and over time will break off the bracket and the blade engagement lever won't activate the switch cause it hanging down. This is just one example of the condition you are having right now. Some have several switches you need to locate and check. Troll or not they need feed also.