I have an E150 and the anti thief light wont let me start my van. The alternartor and battery are both good. I can start it by jumping the solenoid
You didn't state what year, but if it starts and runs by jumping the solenoid it most likely is not the anti thieft system as those usually shut down the ignition also. Could be an ignition switch, park switch, broken wire on the crank circuit.
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